Callus culture development from two varieties of Tagetes erecta and carotenoids production

AbstractBackgroundThe properties of natural pigments, such as antioxidants, functional, medical, and nutraceutical, have demonstrated the advantages of these natural compounds over synthetic ones. Some products are accepted only when they are pigmented with natural, food-quality colorants: for example poultry products (manly marigold flower extracts). Carotenoids such as β-carotene, β-criptoxanthin and lutein are very attractive as natural food colorants due to their antioxidant and pro-vitamin activities which provide additional value to the target products. Marigold (Tagetes erecta) is an Asteraceous ornamental plant native to Mexico, and it is also important as a carotenoid source for industrial and medicinal purposes but nowadays its production is destined mainly for ornamental purposes.ResultsFriable callus of T. erecta yellow flower (YF) and white flower (WF) varieties was induced from leaf explants on Murashige and Skoog (MS) medium supplemented with 9.0μM 4-dichlorophenoxyacetic acid (2,4-D) and 8.8μM benzyladenine (BA). Calluses developed from both varieties were different in pigmentation. Extract characterization from callus cultures was carried out by high-performance liquid chromatography (HPLC). This analytical process detected several carotenoids; the main pigments in extracts from YF callus were lutein and zeaxanthin, whereas in the extracts of the WF callus the main pigments were lutein, zeaxanthin, β-cryptoxanthin and β-carotene. Callus cultures of T. erecta accumulated pigments even after several rounds of subculture.ConclusionsWF callus appeared to be a suitable candidate as a source of different carotenoids, and tested varieties could represent an alternative for further studies about in vitro pigment production

Global human footprint on the linkage between biodiversity and ecosystem functioning in reef fishes

Copyright: © 2011 Mora et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas

Edible Mushrooms: Improving Human Health and Promoting Quality Life

Mushrooms have been consumed since earliest history; ancient Greeks believed that mushrooms provided strength for warriors in battle, and the Romans perceived them as the “Food of the Gods.” For centuries, the Chinese culture has treasured mushrooms as a health food, an “elixir of life.” They have been part of the human culture for thousands of years and have considerable interest in the most important civilizations in history because of their sensory characteristics; they have been recognized for their attractive culinary attributes. Nowadays, mushrooms are popular valuable foods because they are low in calories, carbohydrates, fat, and sodium: also, they are cholesterol-free. Besides, mushrooms provide important nutrients, including selenium, potassium, riboflavin, niacin, vitamin D, proteins, and fiber. All together with a long history as food source, mushrooms are important for their healing capacities and properties in traditional medicine. It has reported beneficial effects for health and treatment of some diseases. Many nutraceutical properties are described in mushrooms, such as prevention or treatment of Parkinson, Alzheimer, hypertension, and high risk of stroke. They are also utilized to reduce the likelihood of cancer invasion and metastasis due to antitumoral attributes. Mushrooms act as antibacterial, immune system enhancer and cholesterol lowering agents; additionally, they are important sources of bioactive compounds. As a result of these properties, some mushroom extracts are used to promote human health and are found as dietary supplements

Study of Plastid Genome Stability in Tobacco Reveals That the Loss of Marker Genes Is More Likely by Gene Conversion Than by Recombination between 34-bp loxP Repeats1[C][OA]

In transformed tobacco (Nicotiana tabacum) plastids, we flank the marker genes with recombinase target sites to facilitate their posttransformation excision. The P1 phage loxP sites are identical 34-bp direct repeats, whereas the phiC31 phage attB/attP sites are 54- and 215-bp sequences with partial homology within the 54-bp region. Deletions in the plastid genome are known to occur by recombination between directly repeated sequences. Our objective was to test whether or not the marker genes may be lost by homologous recombination via the directly repeated target sites in the absence of site-specific recombinases. The sequence between the target sites was the barau gene that causes a golden-yellow (aurea) leaf color, so that the loss of the barau gene can be readily detected by the appearance of green sectors. We report here that transplastomes carrying the barau gene marker between recombinase target sites are relatively stable because no green sectors were detected in approximately 36,000 seedlings (Nt-pSS33 lines) carrying attB/attP-flanked barau gene and in approximately 38,000 seedlings (Nt-pSS42 lines) carrying loxP-flanked barau gene. Exceptions were six uniformly green plants in the Nt-pSS42-7A progeny. Sequencing the region of plastid DNA that may derive from the vector indicated that the barau gene in the six green plants was lost by gene conversion using wild-type plastid DNA as template rather than by deletion via directly repeated loxP sites. Thus, the recombinase target sites incorporated in the plastid genome for marker gene excisions are too short to mediate the loss of marker genes by homologous recombination at a measurable frequency