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Plant DNA: Contents and Systematics
Published in S. K. Dutta, DNA Systematics, 2019
In sharp contrast to this the conifers depict very high DNA values showing a fourfold variation.13 This is because the function of water conduction in conifers is performed by tracheids in contrast to woody angiosperms which have vessels. Therefore, the need for efficient water conduction has resulted in strong selection for bigger cell size as depicted by giant cambial cells in Pinus strobus,132,133 and consequently in increased nuclear volume and DNA content.126 In this context it is significant to note the association of very high DNA values, as in the case of Pinus gerardiana (2C = 57.35 pg), with a temperate and highly xeric habitat.13 It would be worth studying tracheid dimensions vis a vis DNA content in conifer species in relation to ecological conditions. The rarity of polyploidy among gymnosperms may be because the selection for larger genome size has almost reached a saturation point and further increase through polyploidy cannot be tolerated. It is pertinent to remark here that endopolyploidy, which is so characteristic of angiosperms has not so far been found in gymnosperms.134 This may mean that any increase in nuclear and cell size is not tolerated during ontogeny. Furthermore, as this increase in DNA content has taken place by tandem duplications, thereby implying much DNA redundancy, the more active and divergent evolution by (allo)polyploidy has been denied to gymnosperms.66,135–137 Similarly, high DNA values and slow rate of development may have been responsible for the absence of annual habit among gymnosperms.19,126
Plant-Derived Natural Non-Nucleoside Analog Inhibitors (NNAIs) against RNA-Dependent RNA Polymerase Complex (nsp7/nsp8/nsp12) of SARS-CoV-2
Published in Journal of Dietary Supplements, 2023
Sreus A. G. Naidu, Ghulam Mustafa, Roger A. Clemens, A. Satyanarayan Naidu
Suramin, a phytonutrient naturally found in tea from eastern white pine tree needles (Pinus strobus) has been widely used to treat African sleeping sickness and river blindness for over a century (90). Suramin is a polyanionic compound that binds to positively charged patches in DNA or RNA binding proteins (91). Also, suramin is a potent antiviral agent with wide range of effects, including inhibition of viral attachment, viral entry, and viral release from host cells via interactions with viral capsid proteins (92).