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81.
A method for the quantification of aflatoxins B1, G1, B2 and G2 in the medicinal herb Maytenus ilicifolia was developed and validated. The method used immunoaffinity columns for sample clean-up and HPLC with fluorescence detection without any derivatisation step. The method showed good inter-day accuracy (bias values in the range 4.5-10.7%) and precision (5-16% RSD) when applied to the determination of levels of aflatoxins ranging from 7 to 20 ppb in the plant material. The detection limits for samples of the plant material spiked with aflatoxins were 3.5 ng/g for B1 and G1 and 0.1 ng/g for B2 and G2. The method was successfully applied to commercial samples of Maytenus ilicifolia for the screening of aflatoxin contaminants. 相似文献
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R Simões WB Feitosa CM Mendes AC Nicacio FRO de Barros 《Biotechnic & histochemistry》2013,88(3):79-83
Sperm chromatin integrity is essential for accurate transmission of male genetic information, and normal sperm chromatin structure is important for fertilization. Protamine is a nuclear protein that plays a key role in sperm DNA integrity, because it is responsible for sperm DNA stability and packing until the paternal genome is delivered into the oocyte during fertilization. Our aim was to investigate protamine deficiency in sperm cells of Bos indicus bulls (Nelore) using chromomycin A3 (CMA3) staining. Frozen semen from 14 bulls were thawed, then fixed in Carnoy's solution. Smears were prepared and analyzed by microscopy. As a positive control of CMA3 staining, sperm from one bull was subjected to deprotamination of nuclei. The percentage of CMA3-positive bovine sperm did not vary among batches. Only two bulls showed a higher percentage of CMA3-positive sperm cells compared to the others. CMA3 is a simple and useful tool for detecting sperm protamine deficiency in bulls. 相似文献
85.
Timm Konold Gemma E Bone Laura J Phelan Marion M Simmons Lorenzo González Sílvia Sisó Wilfred Goldmann Saira Cawthraw Steve AC Hawkins 《BMC veterinary research》2010,6(1):13
Background
As there is limited information about the clinical signs of BSE and scrapie in goats, studies were conducted to describe the clinical progression of scrapie and BSE in goats and to evaluate a short clinical protocol for its use in detecting scrapie-affected goats in two herds with previously confirmed scrapie cases. Clinical assessments were carried out in five goats intracerebrally infected with the BSE agent as well as five reported scrapie suspects and 346 goats subject to cull from the two herds, 24 of which were retained for further monitoring. The brain and selected lymphoid tissue were examined by postmortem tests for disease confirmation. 相似文献86.
Gabriel G. Perron Lyle Whyte Peter J. Turnbaugh Jacqueline Goordial William P. Hanage Gautam Dantas Michael M. Desai 《PloS one》2015,10(3)
Using functional metagenomics to study the resistomes of bacterial communities isolated from different layers of the Canadian high Arctic permafrost, we show that microbial communities harbored diverse resistance mechanisms at least 5,000 years ago. Among bacteria sampled from the ancient layers of a permafrost core, we isolated eight genes conferring clinical levels of resistance against aminoglycoside, β-lactam and tetracycline antibiotics that are naturally produced by microorganisms. Among these resistance genes, four also conferred resistance against amikacin, a modern semi-synthetic antibiotic that does not naturally occur in microorganisms. In bacteria sampled from the overlaying active layer, we isolated ten different genes conferring resistance to all six antibiotics tested in this study, including aminoglycoside, β-lactam and tetracycline variants that are naturally produced by microorganisms as well as semi-synthetic variants produced in the laboratory. On average, we found that resistance genes found in permafrost bacteria conferred lower levels of resistance against clinically relevant antibiotics than resistance genes sampled from the active layer. Our results demonstrate that antibiotic resistance genes were functionally diverse prior to the anthropogenic use of antibiotics, contributing to the evolution of natural reservoirs of resistance genes. 相似文献
87.
A global meta‐analysis of the relative extent of intraspecific trait variation in plant communities
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Andrew Siefert Cyrille Violle Loïc Chalmandrier Cécile H. Albert Adrien Taudiere Alex Fajardo Lonnie W. Aarssen Christopher Baraloto Marcos B. Carlucci Marcus V. Cianciaruso Vinícius de L. Dantas Francesco de Bello Leandro D. S. Duarte Carlos R. Fonseca Grégoire T. Freschet Stéphanie Gaucherand Nicolas Gross Kouki Hikosaka Benjamin Jackson Vincent Jung Chiho Kamiyama Masatoshi Katabuchi Steven W. Kembel Emilie Kichenin Nathan J. B. Kraft Anna Lagerström Yoann Le Bagousse‐Pinguet Yuanzhi Li Norman Mason Julie Messier Tohru Nakashizuka Jacob McC. Overton Duane A. Peltzer I. M. Pérez‐Ramos Valério D. Pillar Honor C. Prentice Sarah Richardson Takehiro Sasaki Brandon S. Schamp Christian Schöb Bill Shipley Maja Sundqvist Martin T. Sykes Marie Vandewalle David A. Wardle 《Ecology letters》2015,18(12):1406-1419
Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta‐analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole‐plant (e.g. plant height) vs. organ‐level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait‐based community and ecosystem studies. 相似文献
88.
Bruno Ribeiro Gomes Rita de Cássia Siqueira-Soares Wanderley Dantas dos Santos Rogério Marchiosi Anderson Ricardo Soares Osvaldo Ferrarese-Filho 《Plant signaling & behavior》2014,9(12)
In the current work, we investigated the effects of dopamine, an neurotransmitter found in several plant species on antioxidant enzyme activities and ROS in soybean (Glycine max L. Merrill) roots. The effects of dopamine on SOD, CAT and POD activities, as well as H2O2, O2•−, melanin contents and lipid peroxidation were evaluated. Three-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0), without or with 0.1 to 1.0 mM dopamine, in a growth chamber (25°C, 12 h photoperiod, irradiance of 280 μmol m−2 s−1) for 24 h. Significant increases in melanin content were observed. The levels of ROS and lipid peroxidation decreased at all concentrations of dopamine tested. The SOD activity increased significantly under the action of dopamine, while CT activity was inhibited and POD activity was unaffected. The results suggest a close relationship between a possible antioxidant activity of dopamine and melanin and activation of SOD, reducing the levels of ROS and damage on membranes of soybean roots. 相似文献
89.
Daniel Lambertz Chantal Pérot Francis Canon Mariana L.M. Dantas Raul Manhães-de-Castro Karla M. Ferraz 《Journal of electromyography and kinesiology》2013,23(5):1052-1056
The quick-release technique to estimate musculotendinous (MT) stiffness has been extensively used over the last years, in both animals and humans, to gain insights in the adaptive process of the series elastic component (SEC). Recently, MT stiffness quantification, i.e., SEC behavior, has been revisited for subjects not able to fully activate their muscles (effects of long-term spaceflight or non-mature muscles). Such a phenomenon can also be encountered in stunted children. So, the aim of the present study was to analyze the effect of stunting on MT stiffness taking into account possible defect in muscle activation. For this study, 20 eutrophic children (EU) with an average age of 9 years ± 4 months were compared to 11age matched stunted children (S) evaluated by the height-to-age index. The MT stiffness index was obtained with regard to stiffness–torque and stiffness–soleus EMG relationships. The children of the S group presented a significantly lower Maximal Voluntary Contraction (MVC) in plantar flexion in comparison with children of the EU group (?37.8%). The significantly lower MT stiffness index for S children (?42.6%) was evidenced only when quantified with regard to the stiffness–soleus EMG relationship (66.5 ± 42.8 vs. 38.2 ± 19.9 Nm rad?1%?1). Possible delay in fiber type differentiation or tendinous structure maturation can account for the lower MT stiffness index in S children. In conclusion, stunting during early childhood delays the differentiation and maturation processes of musculotendinous structures as shown by the lower MT stiffness quantified with regards to muscle activity, also altered for stunted prepubertal children. 相似文献