Background: Repeat-induced point (RIP) mutation in Neurospora crassa degrades transposable elements by targeting repeats with C→T mutations. Whether RIP affects core genomic sequence in important ways is unknown. Results: By parent-offspring whole genome sequencing, we estimate a mutation rate (3.38 × 10 −6 per bp per generation) that is two orders of magnitude higher than reported for any non-viral organism, with 93-98% of mutations being RIP-associated. RIP mutations are, however, relatively rare in coding sequence, in part because RIP preferentially attacks GC-poor long duplicates that interact in three dimensional space, while coding sequence duplicates are rare, GC-rich, short, and tend not to interact. Despite this, with over 5 coding sequence mutations per genome per generation, the mutational burden is an order of magnitude higher than the previously highest observed. Unexpectedly, the majority of these coding sequence mutations appear not to be the direct product of RIP being mostly in non-duplicate sequence and predominantly not C→T mutations. Nonetheless, RIP-deficient strains have over an order of magnitude fewer coding sequence mutations outside of duplicated domains than RIP-proficient strains. Conclusions: Neurospora crassa has the highest mutation rate and mutational burden of any non-viral life. While the high rate is largely due to the action of RIP, the mutational burden appears to be RIP-associated but not directly caused by RIP.
Ginseng is among the oldest traditional Chinese medicinal herbs and is widely used in China and Southeast Asia. Over the past 50 years, considerable research has focused on the chemical constituents, pharmacological action, and clinical applications of ginseng. In this review, we examine the current state of research on ginseng, including the main active ingredient ginsenoside, its pharmacological effects on the cardiovascular system, and mechanisms of action. We focus on what is known of the effects of ginseng against atherosclerosis, arrhythmia, myocardial ischemia, and its inhibition of ventricular remodeling, providing a basis for expanding the clinical applications of ginseng.
Structural evolution of two ethylene−octene copolymers with different octene content during tensile deformation and recovery was investigated using the in-situ synchrotron small-angle X-ray scattering technique. Sample containing 4 mol % octene shows similar deformation mechanism as observed previously that the whole process of deformation can be regarded as a stretching of two interpenetrating networks of crystalline rigid network and entangled amorphous phase. A transition from a crystalline rigid network dominating behavior at small deformations to a stretching-induced crystalline block disaggregation− recrystallization process occurs at a critical strain where stress generated by the stretched amorphous network reaches a critical value leading to the destruction of crystalline blocks. In sample containing 8 mol % octene, this critical strain is much larger than observed in the other sample. Such a phenomenon is attributed to the fact that only crystalline lamellar stacks and bundle-like crystals with much weakened coupling can be developed in the sample. The weakened coupling between crystalline lamellar stacks is due to the existence of interstack amorphous phase which also leads to an inhomogeneous strain distribution in the system.
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