首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Alzheimer’s disease (AD) is a progressive neurodegenerative disease affecting 25 million people worldwide, and cholinergic hypothesis is considered as an important hypotheses in the processes of improving cognitive function and recognition skills in recent years. For the long-term treatment of AD, traditional Chinese medicine are particularly suitable for drug discovery. In this review, we sum up six traditional Chinese medicinal herbs concerned with development of AChEIs, including Herba Epimedii, Coptis Chinensis Franch, Rhizoma Curcumae Longae, Green tea, Ganoderma, Panax Ginseng. The listed compounds based on these herbs are belonging to six classes Flavonoids, Alkaloids, Ketones, Polyphenols, Terpenoid and Saponins, respectively. These compounds could be very promising agents in the search for potent anti-Alzheimer’s drugs.  相似文献   

2.
This paper reviews the interactions of insects with food packaging, and measures which may be taken to limit damage.  相似文献   

3.
Camel’s milk is an important part of staple diet in several parts of the world, particularly in the arid and semi-arid zones. Camel’s milk is rich in health-beneficial substances, such as bioactive peptides, lactoferrin, zinc, and mono and polyunsaturated fatty acids. These substances could help in the treatment of some important human diseases like tuberculosis, asthma, gastrointestinal diseases, and jaundice. Camel’s milk composition is more variable compared to cow’s milk. The effects of feed, breed, age, and lactation stage on milk composition are more significant in camel. Region and season significantly change the ratio of compounds in camel’s milk. Camel’s whey protein is not only composed of numerous soluble proteins, but also has indigenous proteases such as chymotrypsin A and cathepsin D. In addition to their high nutritional value, these whey proteins have unique characteristics, including physical, chemical, physiological, functional, and technological features that are useful in the food application. The hydrolysis of camel’s milk proteins leads to the formation of bioactive peptides, which affect major organ systems of the body and impart physiological functions to these systems. The camel’s milk has antioxidant, antimicrobial, angiotensin-I-converting enzyme (ACE)-inhibitory peptides, antidiabetic as well as anticholesterol activities.  相似文献   

4.
The present review discusses the concept of mineral neoformation which describes the formation of gypsum as the end-product of analogous processes occurring in the atmosphere, in the lichen thallus and on lithic substrates colonized by lichens. The formation of gypsum occurs as a result of H2SO4 reacting with CaCO3. Climate change, e.g. global warming and desertification led to an increasing number of annual dust storms originating in North African deserts, from 5 days in 1958 to 30 days in 2006, i.e. sixfold in 48 years. Calcium is a major constituent of desert dust. The enlarged dust load in the Eastern Mediterranean coincides with the amount of calcium accumulated in lichens: from 6300 μg g−1 in 1978 to 36,603 ± 7563 μg g−1 in 2002, i.e. about sixfold in 24 years. Desert dust carrying Ca-containing particles reacts with sulfuric acid produced in the atmosphere following both volcanic and anthropogenic activities. Gypsum produced via neoformation in the atmosphere, precipitates in varying formations, e.g. iberulites. A process of neutralization leads to the formation of biominerals. CaCO3-containing particles entrapped in the lichen thallus react with sulfuric acid to produce gypsum as its end-product, detected in the form of crystals on the outer surface of the thallus. The formation of biogenic gypsum occurs also via the reaction of intra- and extracellular Ca2+ cations with SO42− anions, penetrating into, or found inside thallial cells. The catalytic capability of lichens is evident in the process of neoformation of gypsum on lithic substrates, e.g. granite.  相似文献   

5.
Capsule Arrival date strongly influenced date of breeding and breeding success.

Aim To check our hypothesis that in years with low April temperatures, i.e. when storks started to breed, the relationship between timing of breeding and success would be absent, meaning that migrants would have no advantage by returning early to their breeding area.

Methods We collected data in Poznań province, western Poland during the period 1983–2002. Based on local climatological data we selected eight cold spring years and compared them with the 12 ‘normal’ years. We analysed how weather affected the timing and arrival pattern of White Stork.

Results The two groups of years did not differ significantly in population size, but in normal years the arrival date of both parents was earlier. Arrival date strongly influenced (was positively correlated with) date of breeding and (negatively correlated with) breeding success.

Conclusion The slopes describing the above relationships did not differ significantly between the two groups of years. Therefore, we speculate that natural selection strongly favours birds that return early from the wintering grounds.  相似文献   

6.
Coral reefs are among the most biologically diverse and economically important ecosystems on the planet. The deposition of massive calcium carbonate skeletons (biomineralization or calcification) by scleractinian corals forms the coral reef framework/architecture that serves as habitat for a large diversity of organisms. This process would not be possible without the intimate symbiosis between corals and photosynthetic dinoflagellates, commonly called zooxanthellae. Carbonic anhydrases play major roles in those two essential processes of coral’s physiology: they are involved in the carbon supply for calcium carbonate precipitation as well as in carbon-concentrating mechanisms for symbiont photosynthesis. Here, we review the current understanding of diversity and function of carbonic anhydrases in corals and discuss the perspective of theses enzymes as a key to understanding impacts of environmental changes on coral reefs.  相似文献   

7.
Summary Methionine dependence is a defect found in many cancer cell lines that inhibits their growth in culture when methionine is replaced by its immediate precursor, homocysteine, in the culture medium. Normal cultured cells do not have this defect. This report lists the diverse and large number of animal and human cancer lines that are methionine-dependent, and critically reviews the cell biology and methionine biochemistry of the phenomenon. This work was supported by Grant CA27564 from the National Institutes of Health; The Council for Tobacco Research-USA, Inc.; The United Cancer Council, Inc.; The Cancer Research Coordinating Committee of the University of California; Grants from the Academic Senate, University of California, San Diego; and a Special Fellowship to R. M. H. from the Leukemia Society of America. An erratum to this article is available at .  相似文献   

8.
Pollen as food and medicine—A review   总被引:2,自引:0,他引:2  
Pollen, the male gametophyte of flowering plants, is a high energy material, which is collected by insects and stored as food reserve. Pollen has been used traditionally by humans for religious purposes and as supplementary food. Pollen is a concentrated, energy and vitamin rich food that in contemporary times is not only consumed as a dietary component, but also is used in alternative medical treatments. Pollen has potential imporiance as a supplementary and survival food, and for conditioning of athletes. Pollen has been used medically in prostatitis, bleeding stomach ulcers and some infectious diseases, although such use has been questioned by the medical profession. Pollen may also be used for treatment and prevention of the high-altitude-sickness syndrome. Because some individuals are allergic to pollen, and various pollen species contain specific allergens, individual sensitivities must be tested before pollen is used as a treatment or as a supplementary food.  相似文献   

9.
Summary Callus induction and regeneration studies were carried out on a medicinal fern, Drynaria quercifolia native to Asian countries. It is a seasonal fern that regenerates only during the monsoons. Callus was induced on Knop’s (1865) medium supplemented with 20 gl−1 sucrose, 8gl−1 agar, and either 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 4-amino-3,5,6-trichloropicolinic acid (picloram), or indole-3-butyric acid at different concentrations. Morphogenetic callus obtained on 5 mgl−1 2,4,5-T was subcultured onto solid and liquid media (shaken flask and discontinuously stirred bioreactor cultures) for callus proliferation and regeneration studies. A significant amount of sporophyte regeneration was observed on solid medium containing 10 mgl−1 6-(δ, δ-dimethylallylamino) purine (2iP). Sporophyte regeneration from callus followed an atypical pattern of development. Leafy structures of single-cell thickness with a microrhizome were formed as sporophyte initials. Prolonged cultures of these structures resulted in the formation of juvenile sporophytes in vitro. The use of liquid media resulted in increased biomass in culture. The present study is the first report of a successful system for callus production and regeneration of sporophytes from leafy structures in ferns. The method can be successfully applied for generation of biomass of D. quercifolia, throughout the year.  相似文献   

10.
Bees are essential pollinators of many plants in natural ecosystems and agricultural crops alike. In recent years the decline and disappearance of bee species in the wild and the collapse of honey bee colonies have concerned ecologists and apiculturalists, who search for causes and solutions to this problem. Whilst biological factors such as viral diseases, mite and parasite infections are undoubtedly involved, it is also evident that pesticides applied to agricultural crops have a negative impact on bees. Most risk assessments have focused on direct acute exposure of bees to agrochemicals from spray drift. However, the large number of pesticide residues found in pollen and honey demand a thorough evaluation of all residual compounds so as to identify those of highest risk to bees. Using data from recent residue surveys and toxicity of pesticides to honey and bumble bees, a comprehensive evaluation of risks under current exposure conditions is presented here. Standard risk assessments are complemented with new approaches that take into account time-cumulative effects over time, especially with dietary exposures. Whilst overall risks appear to be low, our analysis indicates that residues of pyrethroid and neonicotinoid insecticides pose the highest risk by contact exposure of bees with contaminated pollen. However, the synergism of ergosterol inhibiting fungicides with those two classes of insecticides results in much higher risks in spite of the low prevalence of their combined residues. Risks by ingestion of contaminated pollen and honey are of some concern for systemic insecticides, particularly imidacloprid and thiamethoxam, chlorpyrifos and the mixtures of cyhalothrin and ergosterol inhibiting fungicides. More attention should be paid to specific residue mixtures that may result in synergistic toxicity to bees.  相似文献   

11.
2,2-Diphenyl-1-picrylhydrazyl (DPPH?) radical scavenging, the most commonly used antioxidant method with more than seventeen thousand articles cited, is very practical; however, as with most assays, it has the major disadvantage of dependence on a spectrophotometer. To overcome this drawback, the colorimetric determination of the antioxidant activity using a scanner and freely available Image J software was developed. In this new method, the mixtures of solutions of DPPH? and standard antioxidants or extracts of common medicinal herbs were dropped onto TLC plates, after an incubation period. The spot images were evaluated with Image J software to determine CSC50 values, the sample concentrations providing 50% colour reduction, which were very similar with the SC50 values obtained with spectrophotometric method. The advantages of the new method are the use of lower amounts of reagents and solvents, no need for costly spectrophotometers, and thus significantly lowered costs, and convenient implementation in any environment and situation.  相似文献   

12.
Extensive investigation has shown that khellin, an active principle obtained from this plant, is of value in treating angina pectoris and bronchial asthma.  相似文献   

13.
Gut bacteria play an important role in several metabolic processes and human diseases, such as obesity and accompanying co-morbidities, such as fatty liver disease, insulin resistance/diabetes, and cardiovascular events. Among other factors, dietary patterns, probiotics, prebiotics, synbiotics, antibiotics, and non-dietary factors, such as stress, age, exercise, and climatic conditions, can dramatically impact the human gut microbiota equilibrium and diversity. However, the effect of minor food constituents, including food additives and trace contaminants, on human gut microbiota has received less attention. Consequently, the present review aimed to provide an objective perspective of the current knowledge regarding the impacts of minor food constituents on human gut microbiota and consequently, on human health.  相似文献   

14.
15.
Plantamajoside is a bioactive caffeic acid derivative, a dihydroxyphenethyl glucoside in the group of polyphenolic compounds. It is one of the principal caffeic acid glycoside in the Plantago Digitalis, Hemiphragma, Lagotis, Picrorhiza, Rehmannia, Veronica, Wulfeniopsis and Wulfenia genera within the Plantaginaceae family. This compound is also present in the genera Aeschynanthus and Chirita of the Gesneriaceae family and the genus Boschniakia of the Orobanchaceae family. Plantamajoside is present in the greatest concentrations in roots of young plants, but it is also found in seeds, flower stalks, stems, leaves, in vivo cultivated plant cells and transgenic root cultures. Plantamajoside is used as a biomarker in chemotaxonomical studies, and is a compound with numerous biological applications and considerable pharmacological potential. It is a protective agent against ultra-violet light in plants and acts as antioxidant agent with very low toxicity. In addition, plantamajoside can also be industrially synthesized. This review aims to give an overview of plantamajoside in various plantago species as well as its potential as a biomarker and as a new drug compound.  相似文献   

16.
17.
18.
Rodney Needham 《Ethnos》2013,78(3-4):259-264
Red‐White‐Black as a Mode of Thought: A Study of Triadic Classification by Colours in the Ritual Symbolism and Cognitive Thought of the Peoples of the Lower Congo. Anita Jacobson‐Widding. (Uppsala Studies in Cultural Anthropology, 1.) Uppsala: Acta Universitatis Upsaliensis, distributed by Almqvist & Wiksell International, Stockholm, 1979. 396 pp., bibliography, index; 8 plates, map.  相似文献   

19.
《植物生态学报》2018,42(4):407
苔藓-蓝藻共生体(BCS)能固氮, 是养分贫瘠地区森林氮输入的不可忽视的来源。BCS关系与固氮能力研究为科学认识生态系统氮输入与氮循环过程和机理提供了新的视角和有效途径, 具有重要的理论价值。然而, BCS关系、固氮作用与机理的研究迄今未受到足够关注, 报道较少, 认识仍然是零星而片段化的。基于系统查阅的相关文献, 该文综述了BCS的种类组成与共生关系类型、固氮能力及所固定氮的去向及其影响因素和作用机理, 指出了存在的问题及需要深入关注和亟待突破的4个研究方向。  相似文献   

20.
Chemosystematics is a common tool in systematics and taxonomy of extant plants. Terpenoids have been found to be especially valuable for chemosystematic investigations of conifers. A review of data in the extensive literature revealed some characteristic distribution patterns of sesqui-, di-, and triterpenoids in extant conifer families. The numerous terpenoids can be assigned to approximately 40 sesquiterpenoid, 17 diterpenoid, and only a few triterpenoid structural classes. Some of these terpenoid classes (e.g., cadinanes, humulanes, labdanes, pimaranes) are unspecific and distributed among all conifers. Other structural classes occur in certain clusters of families (e.g., totaranes in Podocarpaceae, Taxodiaceae, and Cupressaceae s.str.) or were restricted to species of only one conifer family (e.g., cuparanes in Cupressaceae s.str.). Cupressaceae s.str. and Taxodiaceae show great similarities in their terpenoid composition (cedranes, thujopsanes) but can be separated by the occurrence of some sesquiterpenoids (cuparanes, widdranes), which were hitherto known only in Cupressaceae s.str. This supports a monophyletic clade of Cupressaceae s.str. within the major Taxodiaceae/Cupressaceae lineage (= Cupressaceae s.l.). Pinaceae differ from the other conifer families because they commonly lack several diterpenoid classes (phenolic abietanes, tetracyclic diterpenoids) and because they contain some distinct sesquiterpenoids (longicyclanes, sativanes), diterpenoids (cembranes), and triterpenoids (serratanes, lanostanes). With the exception of diterpenoid alkaloids (taxanes), Taxaceae contain terpenoids common in the other conifer families. This supports their inclusion as a separate family in the major conifer clade.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号