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排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
Meng L Lozano Y Bombarda I Gaydou E Li B 《Journal of agricultural and food chemistry》2006,54(12):4297-4303
Extraction and concentration at a pilot plant scale of anthocyanins and flavonoids from Perilla frutescens var. frutescens harvested in the Guangzhou area of China were investigated. The study of extraction efficiency using mineral acids and organic acids showed that 0.01 mol/L nitric acid was the most suitable to extract flavonoids from this slightly red leaf cultivar. The red extract contained 12 mg/L (as cyanidin equivalent) anthocyanins and other flavones. The multistep process included cross-flow microfiltration (CFM) with a ceramic type membrane, reverse osmosis (RO), and rotating evaporation (RE). The filtration fluxes were high and constant for CFM (150 L/h/m2 at 0.6 b) and for RO (22 L/h/m2 at 40 b). The red extract was concentrated 9.4 times by RO and then 5.4 times by RE. It contained 422 mg/L anthocyanins, representing 77% of the total extracted anthocyanin. The proportion of flavonoids was found unchanged during processing. The concentrated extract showed a pH of 2.7, and its free acidity was found to be 46% of the acidity added for extraction, because of the buffering capacity of the extract. At the concentration level reached, a crystallized deposit occurred and was identified as tartrate. 相似文献
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3.
New Forests - Monterrey Forestal Ltda conducted a study to determine the effects of different stocking on productivity of Gmelina arborea (gmelina) to age 6 years in Zambrano, Bolívar,... 相似文献
4.
I Rodríguez‐Lozano A Ávalos‐Rodríguez H Castillo‐Juárez F Borderas‐Tordesillas JJ Roa‐Vidal AM Rosales‐Torres 《Reproduction in domestic animals》2014,49(1):27-31
In the spermatozoa of some species, the ubiquitin–proteasome system detects altered proteins and tags them for elimination by the proteasome. In some species' ejaculates, a high proportion of ubiquitinated spermatozoa (i.e. those having ubiquitin bound to the altered or damaged membrane proteins) has been related to infertility. The aim of this study was to assess whether the percentage of ubiquitinated spermatozoa relates to fertility of dairy bulls and whether ubiquitination increases during protein remodelling that occurs during in vitro spermatic capacitation. Thirty‐two frozen semen straws from four high‐fertility (ReproMax®) and four normal‐fertility (Normal) Holstein‐Friesian sires were evaluated. Ubiquitinated and capacitated spermatozoa were quantified by sperm ubiquitin tag immunoassay and chlortetracycline stain, respectively. Fertilizing capacity of sires was assessed by in vitro fertilization. No differences were found between Normal and ReproMax® sires with regard to the observed percentage of ubiquitinated spermatozoa (42.97 ± 3.69% and 49.68 ± 9.27%, respectively; p > 0.05). Additionally, no differences were found in the percentage of ubiquitinated spermatozoa as a consequence of spermatic capacitation in either Normal (42.97 ± 3.69% before capacitation vs 44.67 ± 7.5% after; p > 0.05) or ReproMax® sires (49.68 ± 9.27% before vs 45.05 ± 7.51% after; p > 0.05). The percentage of ubiquitinated spermatozoa in a thawed sperm samples did not correlate with its in vitro fertilizing capacity; thus, this assay does not prove useful to detect in vivo fertility differences between sires. Additionally, protein degradation occurring during remodelling of the spermatozoon plasma membrane during the capacitation process does not seem to involve the ubiquitin–proteasome system. 相似文献
5.
Spermatophore deterioration in pond-reared Penaeus vannamei was studied, and spermatophore quality was evaluated and improved. Sperm production of males collected from grow-out ponds was increased by two techniques: eyestalk ablation using a fresh frozen maturation diet (13% body weight); and laboratory culture using a diet of the formulated feed Nicovita Plus (3% body weight/ d) and frozen squid (2%). Findings are complementary to previous reports that eyestalk ablation improves quality of spermatophores in young (25.7 g) males. The timing of eyestalk ablation for activation of the endocrine mechanism, leading to improved spermatophore quality was also explored. After eyestalk ablation, performed between postmolt and intermolt stages, 26 g males required a minimum of three spermatophore regenerations or 42 d to significantly increase spermatophore size and sperm count. On the other hand, the laboratory culture (2.5 mo) technique improved the quality of spermatophores in successive regenerations for non-ablated males. In the present study, subadult P. vannamei produced spermatophores which, if not transferred or manually ejaculated, gradually deteriorated (successive stages are described), while a new compound spermatophore was being synthesized. 相似文献
6.
Juan Carlos Moreno Saiz Felipe Dom?&#x;nguez Lozano Helios Sainz Ollero 《Biological conservation》2003,113(3):419-431
The transfer of legal responsibilities from the Central Government to the Autonomous Communities ended a tradition of paying little attention to endangered Spanish flora. The studies undertaken to implement the European Natura 2000 network, and to prepare regional ‘Red Data Books’ and lists of protected flora offered a much better view of which species were really at risk. As a consequence, a growing number of botanists is now involved in different aspects of conservation biology. The recent publication of a new Spanish Red List of vascular flora has provided the groundwork for the so-called ‘Threatened Flora Atlas’ project, which will update and homogenise the information on 500 taxa at risk. This project will produce a new Spanish Red Book and monitor the status of 40 selected species. The Spanish strategy for plant conservation is discussed, pointing out some deficiencies, such as the neglect of non-vascular taxa, the uneven and sometimes uncoordinated local policies and the uncertain future of some current initiatives. 相似文献
7.
Touriño S Selga A Jiménez A Juliá L Lozano C Lizárraga D Cascante M Torres JL 《Journal of agricultural and food chemistry》2005,53(12):4728-4735
Pine (Pinus pinaster) bark is a rich source of procyanidin oligomers. From a total polyphenolic extract, we have generated fractions of different procyanidin composition. The mixtures, devoid of gallate esters, were active as free radical scavengers against ABTS(*+), DPPH, and HNTTM. Pine bark fractions were tested for antioxidant activity in solution (hydrogen donation and electron transfer) and emulsion (inhibition of lipid peroxidation) and compared with their galloylated counterparts from grape origin. While galloylation clearly influenced the free radical scavenging efficiency in solution, it did not seem to play a determinant role in protection against lipid peroxidation in emulsion. The fractions were very mild inhibitors of cell proliferation. Because gallate esters appear to interfere with crucial cell functions, gallate free pine procyanidins may be the innocuous chemopreventative agents of choice for many applications in food and skin protection. 相似文献
8.
A heat stable toxin present in needles of ponderosa pine was found to be soluble in methanol, ethanol, chloroform hexanes and 1-butanol. The embryotoxic effects of fresh green pine needles and a chloroform/methanol extract were determined by measuring embryo resorption in pregnant mice. Autoclaving the needles and extract for 1 hour prior to feeding enhanced the embryoresorptive effect by 28% and 32%, respectively. The results of this study revealed that the embryo resorptive dose (ERD50) of heat stable toxin for 1 mouse was 8.95 gms. for fresh green pine needles and 6.46 gms. for autoclaved green pine needles. In addition to embryocidal effects, feeding of the toxin resulted in significant weight loss in adult mice. 相似文献
9.
E A Lozano 《American journal of veterinary research》1986,47(5):1153-1156
Identified and partly identified bacterial isolates were obtained from 48 rams of various breeds that had unilateral or bilateral epididymitis. Most of the animals were approximately 1 year of age; a few were older. Brucella ovis, Actinobacillus spp, Corynebacterium spp, Haemophilus spp, Acinetobacter spp, Escherichia coli, Moraxella spp, Staphylococcus spp, Pasteurella spp, Streptococcus spp, and Chlamydia psittaci were isolated. A vaccine strain of B ovis, isolated species of bacteria, and mixtures of isolates of tissue homogenates containing all isolates except B ovis and C psittaci were inoculated via the mucous membranes of the eyes, nares, and prepuce. Palpable epididymitis was not produced by the inoculations. The vaccine strain of B ovis induced complement-fixation reaction in 11 of 20 rams. 相似文献
10.
Sonia A. Soto‐Rodriguez Rodolfo Lozano‐Olvera Daniel A. Palacios‐Gonzalez Carmen Bolan‐Mejia Karla G. Rendon‐Aguilar 《Journal of the World Aquaculture Society》2019,50(5):1002-1015
The phenotypic characteristics and growth kinetics at several temperatures, salinities, and pH values of three Vibrio parahaemolyticus (Vp) strains with different virulence and one nonpathogenic strain were evaluated. Independent of the virulence of the strain, a high metabolic diversity was found, which yielded different colored phenotypes on the CHROMagar? Vibrio. All strains were resistant to ampicillin and carbenicillin, and Vp AHPND+ organisms were the most sensitive to enrofloxacin. The exponential growth of Vp strains started at 1–2 hr of incubation, although no relationship was observed between the bacterial density and degree of virulence. Moreover, the growth of the most virulent strain was independent of the nutrients in the incubation media during the initial hour postinoculation. No strain grew at 4°C in 0% NaCl and pH 4, but only Vp AHPND+ grew at 44°C. For all strains, the lag phase was proportional to the NaCl concentration, and the growth was better at pH 8–9. However, the Vp AHPND? strain displayed a greater variability, was more sensitive to extreme conditions, and showed a lag phase of 9 hr independent of the pH. 相似文献