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121.
Polyploidy events (polyploidization) followed by progressive loss of redundant genome components are a major feature of plant evolution, with new evidence suggesting that all flowering plants possess ancestral genome duplications. Furthermore, many of our most important crop plants have undergone additional, relatively recent, genome duplication events. Recent advances in DNA sequencing have made vast amounts of new genomic data available for many plants, including a range of important crop species with highly duplicated genomes. Along with assisting traditional forward genetics approaches to study gene function, this wealth of new sequence data facilitates extensive reverse genetics-based functional analyses. However, plants featuring high levels of genome duplication as a result of recent polyploidization pose additional challenges for reverse genetic analysis. Here we review reverse genetic analysis in such polyploid plants and highlight key challenges. 相似文献
122.
- Although considered a key functional trait, little is known about how zooplankton feeding mode affects top‐down regulation of phytoplankton communities. Indeed, copepods are expected to promote the dominance of toxic phytoplankton by selective removal of their edible competitors; however, empirical evidence comparing the effect among calanoid and cyclopoid copepods is lacking.
- We compared the top‐down effects of two copepods with contrasting feeding modes—the calanoid Notodiaptomus iheringi (current feeder) and the cyclopoid Thermocyclops decipiens (ambush feeder) — on the relative and absolute biomass of the filamentous cyanobacterium Raphidiopsis raciborskii co‐cultured with the nutritious eukaryotic phytoplankton Cryptomonas obovata in a week‐long laboratory assay.
- The current feeder had a stronger top‐down effect on the biomass of both prey throughout the experiment, with mass‐specific clearance rates 3–5× higher than ambush feeder. By the end of the experiment, the current feeder significantly reduced cyanobacteria biomass compared to controls while the ambush feeder did not. During the week‐long experiment, the current feeder switched from grazing on edible prey to cyanobacteria as the former became less abundant.
- Contrary to expectation, neither of the copepod species promoted cyanobacterial dominance by the end of the experiment. This is because both grazers, but especially the current feeder, initially increased but subsequently decreased the relative contribution of cyanobacteria to total phytoplankton biomass. Moreover, both copepods decreased the length of cyanobacteria filaments by c. 70%
- Current feeders can switch from edible prey to cyanobacteria when the abundance of shortened filaments surpasses the abundance of edible prey. While top‐down regulation of phytoplankton can be stronger for current feeding copepods, ambush feeding copepods can have a significant role during blooms by shortening cyanobacterial filaments. Hence, the broader role of contrasting copepod feeding traits on phytoplankton communities merits further study.
123.
Species of the genusHypencum are of considerable interest worldwide because of their medicinal properties.In- vitro culture is a useful tool for both multiplication of the genus and studying its economically important secondary metabolites.
Here, we present an effectivein- vitro propagation method forH. bupleuroides. Leaf and internodal expiants excised from 9-week-old,in vitro-germinated seedlings were cultured on a Murashige and Skoog (MS) medium supplemented with benzyladenine (BA; 1.0 or 0.1 mg
L-1) and 2,4-dichlorophenoxyacetic acid (2,4-D; 1.0 or 0.1 mg L1). Depending on the BA and 2,4-D combination used, these cultures produced adventitious shoot buds directly on the surfaces
of both types of explants as well as excessive calli. Numerous shoots were obtained when the calli from both expiant types
were cultured on an MS medium supplemented with 2 mg L-1 BA. Internodal expiants were more responsive than leaf tissues to direct and indirect plant regeneration. After shoots that
regenerated from either the calli or the expiant surface were excised, rooting was best on an MS medium lacking any growth
hormones. These rooted plants were then acclimatized under greenhouse conditions, and 90% of regenerants had survived. Ours
is the first report ofin- vitro plant regeneration fromH. bupleuroides. 相似文献
124.
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126.
Olive leaf extract modulates permethrin induced genetic and oxidative damage in rats 总被引:3,自引:0,他引:3
Permethrin is a common synthetic chemical, widely used as an insecticide in agriculture and other domestic applications. The previous reports indicated that permethrin is a highly toxic synthetic pyrethroid pesticide to human and environmental health. Therefore, the present experiment was undertaken to determine the effectiveness of olive leaf extract in modulating the permethrin induced genotoxic and oxidative damage in rats. The animals used were broadly divided into four (A, B, C and D) experimental groups. Group A rats served as control animals and received distilled water intraperitoneally (n = 5). Groups B and C rats received intraperitoneal injections of permethrin (60 mg kg−1 b.w) and olive leaf extract (500 mg kg−1 b.w), respectively. Group D rats received permethrin (60 mg kg−1 b.w) plus olive leaf extract (500 mg kg−1 b.w). Rats were orally administered their respective feed daily for 21 days. At the end of the experiment rats were anesthetized and serum and bone marrow cell samples were obtained. Genotoxic damage was assessed by micronucleus and chromosomal aberration assays. Total antioxidant capacity and total oxidant status were also measured in serum samples to assess oxidative status. Treatment of Group B with permethrin resulted in genotoxic damage and increased total oxidant status levels. Permethrin treatment also significantly decreased (P < 0.05) total antioxidant capacity level when compared to Group A rats. Group C rats showed significant increases (P < 0.05) in total antioxidant capacity level and no alterations in cytogenetic parameters. Moreover, simultaneous treatments with olive leaf extract significantly modulated the toxic effects of permethrin in Group D rats. It can be concluded that olive leaf extract has beneficial influences and could be able to antagonize permethrin toxicity. As a result, this investigation clearly revealed the protective role of olive leaf extract against the genetic and oxidative damage by permethrin in vivo for the first time. 相似文献
127.
Xu Q Schwarzenbacher R Krishna SS McMullan D Agarwalla S Quijano K Abdubek P Ambing E Axelrod H Biorac T Canaves JM Chiu HJ Elsliger MA Grittini C Grzechnik SK DiDonato M Hale J Hampton E Han GW Haugen J Hornsby M Jaroszewski L Klock HE Knuth MW Koesema E Kreusch A Kuhn P Miller MD Moy K Nigoghossian E Paulsen J Reyes R Rife C Spraggon G Stevens RC van den Bedem H Velasquez J White A Wolf G Hodgson KO Wooley J Deacon AM Godzik A Lesley SA Wilson IA 《Proteins》2006,64(3):808-813
128.
Jin KK Krishna SS Schwarzenbacher R McMullan D Abdubek P Agarwalla S Ambing E Axelrod H Canaves JM Chiu HJ Deacon AM DiDonato M Elsliger MA Feuerhelm J Godzik A Grittini C Grzechnik SK Hale J Hampton E Haugen J Hornsby M Jaroszewski L Klock HE Knuth MW Koesema E Kreusch A Kuhn P Lesley SA Miller MD Moy K Nigoghossian E Okach L Oommachen S Paulsen J Quijano K Reyes R Rife C Stevens RC Spraggon G van den Bedem H Velasquez J White A Wolf G Han GW Xu Q Hodgson KO Wooley J Wilson IA 《Proteins》2006,63(4):1112-1118
129.
Tatiana N. Laremore Kemal Solakyildirim Robert J. Linhardt 《Analytical biochemistry》2010,401(2):236-1370
Separation of milligram amounts of heparin oligosaccharides ranging in degree of polymerization from 4 to 32 is achieved within 6 h using continuous elution polyacrylamide gel electrophoresis (CE-PAGE) on commercially available equipment. The purity and structural integrity of CE-PAGE-separated oligosaccharides are confirmed by strong anion exchange high-pressure liquid chromatography, electrospray ionization Fourier transform mass spectrometry, and two-dimensional nuclear magnetic resonance spectroscopy. The described method is straightforward and time-efficient, affording size-homogeneous oligosaccharides that can be used in sequencing, protein binding, and other structure-function relationship studies. 相似文献
130.
Timothy L Fitzgerald Kemal Kazan Zhongyi Li Matthew K Morell John M Manners 《BMC plant biology》2010,10(1):264