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1.
《Bioorganic & medicinal chemistry》2019,27(15):3279-3284
Photodynamic therapy (PDT) is a treatment method using light and photosensitizers (PSs), which is categorized as a non-invasive surgery treatment for cancers. When the tumor is exposed to a specific light, the PSs become active and generate reactive oxygen species (ROS), mainly singlet oxygen which kills nearby cancer cells. PDT is becoming more widely recognized as a valuable treatment option for localized cancers and pre-cancers of skin as it has no long-term effects on the patient. But, due to the limited penetration rate of light into the skin and other organs, PDT can’t be used to treat large cancer cells or cancer cells that have grown deeply into the skin or other organs. Hence, in this study, our focus centers on synthesizing glucose-conjugated phthalocyanine (Pc) compatible with near-infrared (NIR) irradiation as second-generation photosensitizer, so that PDT can be used in a wider range to treat cancers without obstacles. 相似文献
2.
Akira Nagatani 《Journal of plant research》1997,110(1):123-130
Phytochromes are chromoproteins which mediate several light responses in plants. Phytochrome proteins are encoded by a gene
family which is currently being characterized in several plant species. Analysis of type-specific mutants of two well-characterized
members of the family, PhyA and PhyB, indicates that these proteins have distinct functions. Much remains to be learned about
the mechanisms by which the phytochromes carry out their distinct and diverse functions. It is hoped that information concerning
the localization of phytochromes, at the whole plant and subcellular levels, will aid in elucidating the mechanism of phytochrome
function. This review, which summarizes information about phytochrome distribution, has an emphasis on recent reports in which
the molecular species of phytochrome are differentiated. However, classical data are also included and reinterpreted using
knowledge of the phytochrome family. 相似文献
3.
4.
The uvsC gene of Aspergillus nidulans is a homolog of the RAD51 gene of Saccharomyces cerevisiae. However, with respect to its effects on UV mutagenesis, it differs from the yeast gene, since it seems to be required for
UV mutagenesis; however, this conclusion is based only on data from resting conidia. To further clarify the functional role
of the uvsC gene, we tested the UV mutability of strains bearing a uvsC mutation in resting as well as in germinating conidia, by the p-fluoro-phenyl-alanine resistance test. We also evaluated the mutability of the uvsE mutant which belongs to the same epistatic group. Our results show that the uvsC and uvsE genes do not have a significant role in the mutagenic UV-repair pathway.
Received: 20 January 1998 / Accepted: 22 April 1998 相似文献
5.
The Mg2+ ion-assisted activation mechanism of the active site Tyr8 of a human hematopoietic prostaglandin D2 synthase (H-PGDS) was studied by ultraviolet resonance Raman (UVRR) spectroscopy. Addition of Mg2+ to the native H-PGDS at pH 8.0 resulted in the Y8a Raman band of Tyr8 shifting from 1615 cm−1 to 1600 cm−1. This large shift to lower energy of the tyrosine Y8a vibrational mode is caused by the deprotonation of the tyrosine phenol group promoted by binding of Mg2+. Upon subsequent addition of glutathione (GSH), the Mg2+/H-PGDS solution showed the Tyr8 Raman band shifted to 1611 cm−1, which is 11 cm−1 higher than the frequency of the Mg2+ complex of H-PGDS, but 4 cm−1 lower than the Mg2+ free enzyme. These UVRR observations suggest that the deprotonated Tyr8 in the presence of Mg2+ is re-protonated by the abstraction of H+ from the thiol group of GSH, and that the re-protonated Tyr8 species forms a hydrogen bond with the thiolate anion of GSH. Density functional theory calculations on several model complexes of p-cresol were also performed, which suggested that the pKa and vibrational frequencies of the Tyr8 phenol group are affected by the degree and structure of hydration of the Tyr8 residue. 相似文献
6.
Summary To explain the decline of Hippopha? scrub in the vegetation succession in the dunes of The Netherlands, the growth and nodulation
of Hippopha? plants grown in pots, using soil from an early stage (site AH) and a post-optimum stage (site HP), were investigated.
In HP-soil nodulation, yield, and the nitrogen and phosphorus content of test plants were always lower and the number of necrotic
nodules and the dry matter content were always higher than in AH-soil, even after inoculation with crushed nodules and the
addition of a nutrient solution. Plants in HP-soil also had darker roots, less root hairs, a higher number of short lateral
roots and a higher percentage of dead roots than those in AH-soil. These characteristics of adverse growth conditions disappeared
upon ignition or gamma-irradiation of HP-soil.
Possible explanations of these results are discussed. The degeneration of Hippopha? scrub cannot be ascribed to the age of
the plants, the absence of sufficient infective endophyte particles or to abiotic factors such as unfavourable physical (particle
size) or chemical soil conditions but is caused by biotic factors. No indications were obtained that plant-pathogenic fungi
and bacteria are involved. HP-soil in contrast to AH-soil, however, contained large numbers of the nematodeLongidorus sp., a species known to cause root deformations. The conclusion was that this nematode is one of the biotic factors involved
in the degeneration of the Hippopha? scrub. This degeneration is due to a restriction of the root system resulting in a low
phosphate uptake, a low nodulation capacity and, as a consequence, a low nitrogen content. The results demonstrate that biotic
soil factors are important in influencing succession in higher plant communities. 相似文献
7.
The CNS (central nervous system) is unquestionably the central organ that regulates directly or indirectly all physiological systems in the mammalian body. Yet, when considering the defence of the CNS from pathogens, the CNS has often been considered passive and subservient to the pro-inflammatory responses of the immune system. In this view, neuroinflammatory disorders are examples of when the tail (the immune system) wags the dog (the CNS) to the detriment of an individual''s function and survival. 相似文献
8.
9.
To discover new phytoalexins, an 80% MeOH extract of UV-irradiated rice leaves was analyzed using LC–MS, resulting in the detection of three unidentified compounds. We isolated the compounds from the UV-irradiated rice leaves using chromatographic methods and identified the compounds as N-benzoyltyramine (1), and two casbene-type diterpenes, 5-dihydro-ent-10-oxodepresssin (2) and 5-deoxo-ent-10-oxodepressin (3), using spectroscopic methods. Additionally, we compared the accumulation levels of major UV-inducible compounds in response to Magnaporthe oryzae inoculation and the antifungal activities of the compounds against M. oryzae colony growth. Although 1–3 showed negligible antifungal activity against M. oryzae, the compounds significantly accumulated in M. oryzae-inoculated rice leaves. Furthermore, we confirmed that N-benzoyltryptamine and N-cinnamoyltryptamine also accumulated after M. oryzae inoculation and have relatively high antifungal activity against M. oryzae to the same extent as phytocassanes. These results strongly support the hypothesis that the two amides are rice phytoalexins. 相似文献
10.
Monocotyledons of 104 species in 52 families were divided into two groups depending on the UV fluorescence behaviour of their cell walls. The unlignified cell walls of the first group, fluoresced blue, which changed to green with increased intensity after treatment with NH3 due to the presence of bound ferulic acid. The isolated cell walls of members of the first group were shown to contain bound ferulic, p-coumaric and diferulic acids. These acids were absent from cell walls of the second group. The first group contained families of the Commelinidae of Cronquist, the Palmae (part of the Arecidae), and the Philydraceae, Pontederiaceae, and Haemodoraceae (all part of Liliidae). The other families of the latter two subclasses and those of the Alismatidae belonged to the second group. 相似文献