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11.
The effects of light intensity and spectral quality on growth and shoot initiation in tobacco callus 总被引:5,自引:0,他引:5
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The effects of eight different narrow band-emitting fluorescent lamps (371-750 nm) and four commercial broad band-emitting fluorescent sources upon growth and shoot initiation in tobacco callus (Nicotiana tabacum var. Wisconsin 38) have been characterized. Wavelength and intensity are equally important parameters in determining morphogenic changes. Near ultraviolet light (371 nm) was found to stimulate (0.024 mw/cm2) or inhibit (above 0.15 mw/cm2) callus growth and shoot initiation, depending on the light intensity. Stimulation of growth and shoot production occurs also in blue light region, but at higher intensity than in the near ultraviolet. Red and far red light (up to 1.7 mw/cm2) do not appear to affect callus growth or stimulate shoot initiation. The enhancement of callus growth and the stimulation of shoot initiation are controlled by the same near ultraviolet-absorbing photoreceptor system present in a small enough concentration that it cannot be recognized in the absorption spectrum of the intact tissue. Carotenoids, porphyrins, and phytochrome associated with the high irradiance response do not appear to qualify as the photoreceptor. Flavonoids are possible candidates. Radiation emitted by fluorescent lamps outside the near visible region was determined, and we concluded that energy levels were not sufficient to affect the reported results. The spectral output of several commercial lamps in the visible and near visible regions is such that there could be different effects on growth and development of tissue cultures. 相似文献
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A range of phenolic compounds were found in leaves of three cotton species. Water and nutrient stress (sulfur deficiency) both caused a significant decrease in phenolic content. Possible interpretations of the observed phenomena are given. 相似文献
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Ratajczak Mariusz Z. Adamiak Mateusz Bujko Kamila Thapa Arjun Pensato Valentina Kucia Magda Ratajczak Janina Ulrich Henning 《Purinergic signalling》2020,16(2):153-166
Purinergic Signalling - Bone marrow (BM) as an active hematopoietic organ is highly sensitive to changes in body microenvironments and responds to external physical stimuli from the surrounding... 相似文献
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Faisan Joseph P. Luhan Ma. Rovilla J. Sibonga Rema C. Mateo Jonalyn P. Ferriols Victor Marco Emmanuel N. Brakel Janina Ward Georgia M. Ross Stuart Bass David Stentiford Grant D. Brodie Juliet Hurtado Anicia Q. 《Journal of applied phycology》2021,33(4):2391-2405
Journal of Applied Phycology - Farmed eucheumatoids are the top aquaculture commodity in the Philippines, contributing more than 60% of total national aquaculture production by volume. Despite... 相似文献
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Sandra M. Miltsch Jürgen Krücken Janina Demeler Sabrina Ramünke Achim Harder Georg von Samson-Himmelstjerna 《Parasitology international》2013,62(6):591-598
Due to the increasing development of anthelmintic resistance in nematodes worldwide, it is important to search for anthelmintic compounds with new modes of action and also to investigate the possibility to combine compounds with possible synergistic effects. There might also be the chance to take advantage of the fact that nematode populations which have developed resistance against one anthelmintic class might respond hypersusceptibly to another drug class. The aim of this study was to investigate responses of Caenorhabditis elegans populations with mutations in neuro-muscular ion channels to different anthelmintic classes. Furthermore, potential synergistic effects between two anthelmintic compounds from different classes, i.e. emodepside and tribendimidine, were studied. Although there was neither a synergistic nor an antagonistic effect between emodepside and tribendimidine, other types of interactions could be identified. The C. elegans GABAA-receptor (GABAA-R) unc-49 mutants, showing decreased emodepside susceptibility, were more susceptible to tribendimidine than wild-type C. elegans. In contrast, the reverse phenomenon – hypersusceptibility to emodepside in tribendimidine resistant acetylcholine-receptor (AChR) loss of function mutants – was not observed. Moreover, the slo-1 mutant strain (completely emodepside resistant) also showed hypersusceptibility to piperazine. Interestingly, neither the GABAA-R unc-49 mutants nor the AChR mutants showed decreased susceptibility against piperazine, although there were some studies that indicated an involvement of GABAA-R or AChR in the piperazine mode of action. In conclusion, the present study provides evidence suggesting that interactions between commercially available anthelmintic drugs with different modes of action might be a relatively common phenomenon but this has to be carefully worked out for each anthelmintic and each anthelmintic drug combination. Moreover, results obtained in C. elegans will have to be confirmed using parasitic nematodes in the future. 相似文献
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Barbara Stopa Anna Jagusiak Leszek Konieczny Barbara Piekarska Janina Rybarska Grzegorz Zemanek Marcin Król Piotr Piwowar Irena Roterman 《Journal of molecular modeling》2013,19(11):4731-4740
Congo red dye as well as other eagerly self-assembling organic molecules which form rod-like or ribbon-like supramolecular structures in water solutions, appears to represent a new class of protein ligands with possible wide-ranging medical applications. Such molecules associate with proteins as integral clusters and preferentially penetrate into areas of low molecular stability. Abnormal, partly unfolded proteins are the main binding target for such ligands, while well packed molecules are generally inaccessible. Of particular interest is the observation that local susceptibility for binding supramolecular ligands may be promoted in some proteins as a consequence of function-derived structural changes, and that such complexation may alter the activity profile of target proteins. Examples are presented in this paper. 相似文献
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While uniparental transmission of mtDNA is widespread and dominating in eukaryotes leaving mutation as the major source of genotypic diversity, recently, biparental inheritance of mitochondrial genes has been demonstrated in reciprocal crosses of Pelargonium zonale and P. inquinans. The thereby arising heteroplasmy carries the potential for recombination between mtDNAs of different descent, i.e. between the parental mitochondrial genomes. We have analyzed these Pelargonium hybrids for mitochondrial intergenomic recombination events by examining differences in DNA blot hybridization patterns of the mitochondrial genes atp1 and cob. Further investigation of these genes and their flanking regions using nucleotide sequence polymorphisms and PCR revealed DNA segments in the progeny, which contained both P. zonale and P. inquinans sequences suggesting an intergenomic recombination in hybrids of Pelargonium. This turns Pelargonium into an interesting subject for studies of recombination and evolutionary dynamics of mitochondrial genomes. 相似文献
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Irene Ramos Elena Carnero Dabeiba Bernal-Rubio Christopher W. Seibert Liset Westera Adolfo García-Sastre Ana Fernandez-Sesma 《Journal of virology》2013,87(5):2430-2440
The influenza virus nonstructural protein 1 (NS1) inhibits innate immunity by multiple mechanisms. We previously reported that NS1 is able to inhibit the production of type I interferon (IFN) and proinflammatory cytokines in human primary dendritic cells (DCs). Here, we used recombinant viruses expressing mutant NS1 from the A/Texas/36/91 and A/Puerto Rico/08/34 strains in order to analyze the contribution of different NS1 domains to its antagonist functions. We show that the polyadenylation stimulating factor 30 (CPSF30) binding function of the NS1 protein from A/Texas/36/91 influenza virus, which is absent in the A/Puerto Rico/08/34 strain, is essential for counteracting these innate immune events in DCs. However, the double-stranded RNA (dsRNA) binding domain, present in both strains, specifically inhibits the induction of type I IFN genes in infected DCs, while it is essential only for inhibition of type I IFN proteins and proinflammatory cytokine production in cells infected with influenza viruses lacking a functional CPSF30 binding domain, such as A/Puerto Rico/08/34. 相似文献