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151.
It has been well-established that many epiphytic bromeliads of the atmospheric-type morphology, i.e., with leaf surfaces completely covered by large, overlapping, multicellular trichomes, are capable of absorbing water vapor from the atmosphere when air humidity increases. It is much less clear, however, whether this absorption of water vapor can hydrate the living cells of the leaves and, as a consequence, enhance physiological processes in such cells. The goal of this research was to determine if the absorption of atmospheric water vapor by the atmospheric epiphyte Tillandsia usneoides results in an increase in turgor pressure in leaf epidermal cells that subtend the large trichomes, and, by using chlorophyll fluorescence techniques, to determine if the absorption of atmospheric water vapor by leaves of this epiphyte results in increased photosynthetic activity. Results of measurements on living cells of attached leaves of this epiphytic bromeliad, using a pressure probe and of whole-shoot fluorescence imaging analyses clearly illustrated that the turgor pressure of leaf epidermal cells did not increase, and the photosynthetic activity of leaves did not increase, following exposure of the leaves to high humidity air. These results experimentally demonstrate, for the first time, that the absorption of water vapor following increases in atmospheric humidity in atmospheric epiphytic bromeliads is mostly likely a physical phenomenon resulting from hydration of non-living leaf structures, e.g., trichomes, and has no physiological significance for the plant's living tissues. 相似文献
152.
Nathan Woodbury Margo Moore Gerhard Gries 《Entomologia Experimentalis et Applicata》2013,147(2):160-166
The firebrat, Thermobia domestica (Packard) (Thysanura: Lepismatidae), aggregates in response to the faeces of conspecifics. This aggregation response is mediated by two microbial symbionts, the bacterium Enterobacter cloacae (Jordan) Hormaeche & Edwards (Enterobacteriaceae) and the fungus Mycotypha microspora Fenner (Mucorales). Our objective was to determine how these microbes are transmitted between firebrats. We produced fluorescently labelled E. cloacae and M. microspora and presented them to firebrats. Firebrats consumed large quantities of these labelled microbes and deposited them with their faeces where they proliferated rapidly. Firebrats did not harbour E. cloacae or M. microspora within their ovarioles or eggs, and thus cannot transmit them transovarially. Instead, firebrats acquired them horizontally whenever they fed on microbe‐contaminated material, such as faeces, faeces‐contaminated paper, or egg surfaces. Firebrats moult throughout their life, and with each moult they shed the cuticular lining of their digestive tract and likely any microbes residing therein. Because firebrats remain in close contact and live in groups of mixed age and gender, newly moulted individuals can readily re‐acquire E. cloacae or M. microspora from group members. This ensures the perpetuation of their microbial aggregation and arrestment signal. 相似文献
153.
154.
Kumudini Tota Nihar Rayabarapu Sowmya Moosa Venu Talla Balaji Bhyravbhatla Srinivasa Rao 《Bioinformation》2013,9(7):378-380
According to International Diabetes Federation (IDF), India has 62.4 million people with diabetes and by 2030 it is predicted that
the number will rise to 100 million. Studies claim that there are around 410 experimentally proven Indian medicinal plants which
have anti-diabetic activity, of which the mechanism of action of 109 plants has been elucidated or reported. So, the need of the hour
is to explore the claims of Indian medicinal flora and open up the facets of many Indian plants which are being examined for their
beneficial role in diabetes. So, we created a database (InDiaMed) of Indian medicinal plants that captures their role in anti-diabetic
activity. InDiaMed''s features include chemical, pharmacological, biochemical and geographical information of the medicinal plant,
scientifically relevant information of the plant, and the coherent research done on it in the field of diabetes. The database also
includes the list of poly-herbal formulations which are used for treatment of diabetes in India.
Availability
http://www.indiamed.info 相似文献155.
为研究6-甲基-5-庚烯-2酮(MHO)诱导苹果虎皮病发病以及对果皮活性氧代谢的影响,该实验将冷藏210d的红星苹果用0.5、1.0、2.0mL/L的MHO进行外源处理后,测定其内源MHO含量,在25℃下放置10d后,期间定期测定货架期果皮中的MDA、O2.-、H2O2含量,以及PPO、SOD、CAT、POD活性的变化。结果表明,随着MHO处理浓度的增加,红星苹果果皮中MDA、O2.-、H2O2的含量也随之增加;果皮中的PPO活性逐渐上升,SOD、CAT、POD的活性随着MHO的处理浓度增加而降低;随着MHO处理浓度的增加,果实虎皮病的发病率也随之升高,同时果皮内源MHO含量也随之逐渐增加。研究认为,外源MHO可能通过降低抗氧化酶活性进而参与苹果虎皮病的发病过程。 相似文献
156.
在温室盆栽条件下,研究丛枝菌根(AM)真菌地表球囊霉(Glomus versiforme)对连作土壤中西瓜自根苗和嫁接苗生长、根系膜透性、丙二醛(MDA)含量和防御性酶活性的影响.结果表明: 接种AM真菌能显著增加西瓜自根苗和嫁接苗的生物量,提高根系活力,降低根系膜透性和MDA含量.接种AM真菌的自根苗地上部鲜质量、地上部干质量和根系活力分别增加了57.6%、60.0%和142.1%,而接种AM真菌的嫁接苗分别增加了26.7%、28.0%和11.0%;自根苗(C)、嫁接苗(G)、接种AM真菌自根苗(C+M)和接种AM真菌嫁接苗(G+M)的根系细胞膜透性为C>G>C+M>G+M,根系MDA含量为C>G>G+M>C+M.接种AM真菌能提高西瓜自根苗和嫁接苗根系的苯丙氨酸解氨酶(PAL)、过氧化氢酶(CAT)、过氧化物酶(POD)、几丁质酶和β 1,3 葡聚糖酶活性,而且接种AM真菌的西瓜自根苗和嫁接苗根系POD、PAL和β-1,3-葡聚糖酶活性的峰值比不接种的提前2周出现.接种AM真菌能激活西瓜自根苗和嫁接苗与抗逆性有关的防御性酶反应,使根系对逆境产生快速反应,从而提高其抗连作障碍的能力. 相似文献
157.
杜仲主要生物活性研究进展 总被引:1,自引:0,他引:1
杜仲作为传统滋补药材引起人们广泛的关注.通过从作用机理与实验研究方法等方面综述近些年来杜仲在降血压、抗氧化、抗疲劳、增强免疫作用、抗骨质疏松、抗肿瘤、保肝护肝、降血糖和抗衰老等生物活性的研究进展,旨在为深入了解杜仲的活性功效,进一步开展相关研究提供参考. 相似文献
158.
本文对高等真菌绵地花(Albatrellus ovinus)进行了化学成分的研究。利用各种柱色谱方法(包括正相硅胶、反相硅胶、Sephadex LH-20凝胶色谱、中压液相色谱、半制备HPLC等),分离得到grifolin及其它的5个衍生物。分别为grifolin(1)、neogrifolin(2)、grifolinone A(3)、grifolinone C(4)、confluentin(5)和4-O-methylgrifolic acid(6)。这些化合物的结构通过波谱学方法以及与文献数据对照进行确定。化合物3~6为首次从该种高等真菌中分离得到。化合物4为一个真菌色素,它是一个由一分子的grifolin和一分子苯醌化的grifolin以头对头的方式聚合而成的二聚体。 相似文献
159.
William G. Meikle Marie-Claude Bon Steve C. Cook Carlos Gracia Stefan T. Jaronski 《Biocontrol Science and Technology》2013,23(2):220-233
Two strains of Pseudomonas fluorescens were found contaminating a biopesticide used in a previous study against Varroa destructor infestations in honey bee hives. In that study, the biopesticide, a formulation of a fungal pathogen of arthropods, Beauveria bassiana, failed to have any negative impact on the mite infestation despite successful results in previous studies using uncontaminated batches of the same biopesticide. The objective of the present research was to determine whether the bacteria may have interfered with the infectivity and/or virulence of B. bassiana in a simplified system; positive results in that system would then provide a rationale for further work under more complex conditions. Galleria mellonella late instar larvae treated topically with both a bacterial suspension of 6.8 to 7.0×107 cfu/ml and a fungal suspension of 2.5×107 or 2.5×108 B. bassiana conidia/ml showed, in the case of one of the bacterial strains, significantly increased survivorship compared to larvae treated with just the B. bassiana suspension. When larvae were immersed in a bacterial suspension prior to application of B. bassiana suspension using a spray tower, a significant positive effect of the same P. fluorescens strain on larval survivorship was observed at 2.5×108 conidia/ml. Neither the bacterial suspensions alone nor blank control solutions had any effect on larval survivorship. These results show that an interaction between the bacteria and the pathogen may explain some of the results from the prior field trial. 相似文献
160.
Nitrogenase catalyzes not only the reduction of N2 to NH3 but also the reduction of C2H2 to C2H4 and H+ ion to H2 gas, etc. The detailed mechanism of the nitrogenase reaction is not clear. We have prepared monoclonal antibodies against Component I nitrogenase of A. vinelandii and examined the effects of antibodies on the nitrogenase reactions. A monoclonal antibody designated MA-1 inhibited C2H2 reduction activity strongly but did not inhibit H2 evolution activity. MA-2, on the contrary, inhibited only H2 evolution activity. MA-8 inhibited both C2H2 reduction and H2 evolution activity to the same extent. 相似文献