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排序方式: 共有396条查询结果,搜索用时 31 毫秒
151.
Louisi Souza de Oliveira Diogo Antonio Tschoeke Aline Santos de Oliveira Lilian Jorge Hill Wladimir Costa Paradas Leonardo Tavares Salgado Cristiane Carneiro Thompson Renato Crespo Pereira Fabiano L. Thompson 《Marine drugs》2015,13(2):879-902
The red seaweeds belonging to the genus Laurencia are well known as halogenated secondary metabolites producers, mainly terpenoids and acetogennins. Several of these chemicals exhibit important ecological roles and biotechnological applications. However, knowledge regarding the genes involved in the biosynthesis of these compounds is still very limited. We detected 20 different genes involved in the biosynthesis of terpenoid precursors, and 21 different genes coding for terpene synthases that are responsible for the chemical modifications of the terpenoid precursors, resulting in a high diversity of carbon chemical skeletons. In addition, we demonstrate through molecular and cytochemical approaches the occurrence of the mevalonate pathway involved in the biosynthesis of terpenes in L. dendroidea. This is the first report on terpene synthase genes in seaweeds, enabling further studies on possible heterologous biosynthesis of terpenes from L. dendroidea exhibiting ecological or biotechnological interest. 相似文献
152.
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154.
Leonardo J. Solmesky Avi Zrachya Galina Denisova Yedidya Gafni Jonathan M. Gershoni 《Phytoparasitica》2010,38(2):201-208
Tomato yellow leaf curl virus (TYLCV) is a begomovirus that seriously threatens tomato crops worldwide. Current immunodiagnostic methods for this pathogen
employ commercially produced mAbs raised against TYLCV. However, despite the existence of these mAbs, little information regarding
their characterization or strategy of production has been published. In addition, research on TYLCV would certainly benefit
were more mAbs available, thus allowing efficient examination of the virus life cycle, modes of pathogenesis and possibly
the development of resistant cultivars. The coat protein (CP) of TYLCV is the only known building block of the viral capsid.
Therefore, in this study we used CP as an immunogen for the production of novel mAbs. We employed a strategy in which the
CP was truncated at its C-terminus to avoid intra- and inter-protein interactions that could impair epitope exposure. For
the same reason, we used a denaturated antigen to expose linear epitopes during the immunization. This effort yielded three
mAbs: they were characterized biochemically and immunologically, and their epitopes were mapped. Possible applications of
these mAbs are discussed. 相似文献
155.
Leonardo Cesar Ferreira Ana Catarina Cataneo Natália Corniani Yara Andréo de Souza Bruno José Aparecido Soares 《Pesticide biochemistry and physiology》2010,97(1):47-54
Nitric oxide (NO) is a molecule able to directly scavenge ROS and end chain reactions, which can be generated by some herbicides. This study aimed to evaluate whether the pretreatment of soybean plants with sodium nitroprusside (SNP) solution, a NO-donor substance, provides protection against oxidative stress generated by lactofen. Soybean plants were pretreated with SNP before lactofen application. The levels of lipoperoxides and photosynthetic pigments were quantified, and the activity of the antioxidant enzymes glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) was assessed. Although lipid peroxidation was not completely prevented, NO was able to scavenge ROS generated by the lactofen action, avoiding the photosynthetic pigment breakdown. Consequently, ROS scavenging by NO leads to a decrease in the available substrate for the antioxidant enzymes SOD, CAT, and POD, which are essential to protect plants under oxidative stress situations such as absence of GST induction by H2O2. 相似文献
156.
Amorim TM Macedo LL Uchoa AF Oliveira AS Pitanga JC Macedo FP Santos EA de Sales MP 《Journal of agricultural and food chemistry》2008,56(17):7738-7745
The digestive system of P. interpunctella was characterized during its larval development to determine possible targets for the action of proteinaceous enzyme inhibitors and chitin-binding proteins. High proteolytic activities using azocasein at pH 9.5 as substrate were found. These specific enzymatic activities (AU/mg protein) showed an increase in the homogenate of third instar larvae, and when analyzed by individual larvae (AU/gut), the increase was in sixth instar larvae. Zymograms showed two bands corresponding to those enzymatic activities, which were inhibited by TLCK and SBTI, indicating that the larvae mainly used serine proteinases at pH 9.5 in their digestive process. The presence of a peritrophic membrane in the larvae was confirmed by chemical testing and light microscopy. In a bioassay, P. interpunctella was not susceptible to the soybean trypsin inhibitor, which did not affect larval mass and mortality, likely due to the weak association with its target digestive enzyme. EvV (Erythrina velutina vicilin), when added to the diet, affected mortality (LD50 0.23%) and larval mass (ED50 0.27%). This effect was associated with EvV-binding to the peritrophic membrane, as seen by immunolocalization. EvV was susceptible to gut enzymes and after the digestion process, released an immunoreactive fragment that was bound to the peritrophic matrix, which probably was responsible for the action of EvV. 相似文献
157.
Pittarello Marco Busato Jader Galba Carletti Paolo Sodré Fernando Fabriz Dobbss Leonardo Barros 《Journal of Soils and Sediments》2019,19(3):1554-1565
Journal of Soils and Sediments - The external supply of humic substances has been recently suggested for the remediation of metal-polluted sediments; however, little is known about how to supply... 相似文献
158.
The potential of near-infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of seed weight, total oil content
and its fatty acid composition in intact single seeds of rapeseed was studied. A calibration set of 530 single seeds was analysed
by both NIRS and gas-liquid chromatography (GLC) and calibration equations for the major fatty acids were developed. External
validation with a set of 75 seeds demonstrated a close relationship between NIRS and GLC data for oleic (r = 0.92) and erucic
acid (r = 0.94), but not for linoleic (r = 0.75) and linolenic acid (r = 0.73). Calibration equations for seed weight and
oil content were developed from a calibration set of 125 seeds. A gravimetric determination was used as reference method for
oil content. External validation revealed a coefficient of correlation between NIRS and reference methods of 0.92 for both
traits. The performance of the calibration equations for oleic and erucic acid was further studied by analysing two segregating
F2 seed populations not represented in the calibration set. The results demonstrated that a reliable selection for both fatty
acids in segregating populations can be made by using NIRS. We concluded that a reliable estimation of seed weight, oil content,
oleic acid and erucic acid content in intact, single seeds of rapeseed is possible by using NIRS technique.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
159.
Andressa Teles Joan Salas-Leiva Carlos Alfonso Alvarez-González Enric Gisbert Leonardo Ibarra-Castro Juan Carlos Pérez Urbiola Dariel Tovar-Ramírez 《Fish physiology and biochemistry》2017,43(6):1613-1628
This work contributes basic knowledge on larval development of Seriola rivoliana. A histological study describes the development of the digestive tract and accessory glands in S. rivoliana larvae reared under laboratory conditions at 24 °C from hatching to 30 days post-hatching (DPH). At hatching (2.6 ± 0.12 mm), larvae had an undifferentiated digestive tract with a closed straight tube and a large yolk sac with an oil globule. The liver and pancreas were observed at 1 and 2 days, and the mouth and anus opened at day 2. Enriched rotifers were visible in their digestive tract. At the beginning of the pre-flexion stage, a mixed nutritional period was observed. At day 3, exogenous feeding began; the digestive tract became differentiated into the buccopharynx, esophagus, an undifferentiated stomach, and the intestines. Zymogen granules were visible in the exocrine pancreas. At day 4, supranuclear vacuoles were present in the posterior intestine, indicating the beginning of intracellular digestion. At day 5, goblet cells were present in the esophagus and became functional at day 7 in the esophagus and intestine. The buccopharynx goblet cells developed at day 15. The presence of gastric glands and differentiation of the stomach in the fundic, cardiac, and pyloric regions during the post-flexion stage occurred at day 20. This was the onset of the juvenile period and the beginning of weaning; however, a long co-feeding phase is recommended. Pyloric caeca were observed at day 30 (13.6 ± 1.6 mm). These results provide valuable information on S. rivoliana larvae biology and digestive physiology, which should be useful to improve cultivation techniques and identify ecological features involved in ontogeny. 相似文献
160.
Tomas Martinez-Trinidad W. Todd Watson Michael A. Arnold Leonardo Lombardini 《Urban Forestry & Urban Greening》2009,8(1):41-48
Some practitioners within the green industry have lauded the application of sugar-containing products to the soil around trees as a method to improve plant health. A research study was initiated to evaluate the effects of exogenous applications of glucose and starch on the growth and vitality of healthy live oaks (Quercus virginiana P. Miller). Glucose, starch, or a 50:50 mixture of both carbohydrates were applied as soil drenches around 60 young live oaks growing at a field nursery. Carbohydrates were dissolved in water and applied at concentrations of 0, 40, 80, and 120 g L?1 within 0.5 m from the trunk. Solutions were applied using 10 L per application every four months during an 18-month period. Trunk diameter, root and canopy growth, and carbohydrate content of twigs and roots were measured every four months, and net photosynthetic rate, chlorophyll fluorescence, and soil respiration were measured every six months. Tissue samples from twigs and roots were collected after 16 months to measure carbon isotope composition (δ13C) as an indicator of carbohydrate uptake. Chlorophyll fluorescence varied throughout the experiment but did not demonstrate a clear trend. Higher carbohydrate applications did influence the concentration of glucose in twigs although the results did not clearly indicate that this effect was caused by an uptake of glucose from roots. δ13C signatures did not provide any evidence about potential carbohydrate uptake. Even though there was a significant increase in soil respiration after being treated with starch, no significant increase in growth or vitality was detected on healthy live oaks. 相似文献