ZHAO, L. | bioRxiv Science

bioRxiv2023

The heterogeneity and effect of diabetes and hypertension on spectral characteristics of vasomotion

Vasomotion refers to the spontaneous oscillation of blood vessels within a frequency range of 0.01 to 1.6 Hz. Various disease states, including hypertension and diabetes, have been associated with alterations in vasomotion at the finger, indicating potential impairment of skin microcirculation. Due to the non-linear nature of human vasculature, the modification of vasomotion may vary across different locations for different diseases. In this study, Laser Doppler Flowmetry was used to measure blood flow motion at acupoints LU8, LU5, SP6, and PC3 among 49 participants with or without diabetes and/or hypertension. Fast Fourier Transformation was used to analyze noise type while Hilbert-Huang Transformation and wavelet analysis were applied to assess Signal Noise Ratio (SNR) results. Statistical analysis revealed that different acupoints exhibit distinct spectral characteristics of vasomotion not only among healthy individuals but also among patients with diabetes and hypertension. The results showed strong heterogeneity of vasomotion among blood vessels, indicating that the vasomotion measured at a certain point may not reflect the real status of microcirculation.

bioengineering↗

bioRxiv2022

ATG5- and ATG7-mediated autophagy regulates pollen tube guidance and male fertility in Arabidopsis thaliana

Autophagy functions as a crucial cellular scavenger by targeting cytoplasmic cargo to specific lysosome/vacuole for degradation. Autophagy-related (ATG) core proteins including ATG5 and ATG7 are evolutionarily conserved factors that are spatiotemporally orchestrated to regulate multiple processes of autophagy in yeast, mammalian and plant cells. However, autophagy is believed to be functionally dispensable in Arabidopsis thaliana since severe defects during plant growth, development and reproduction have not been observed in most of the ATG loss-of-function mutants, including atg5 and atg7, under standard cultivation conditions. In this study, we report that autophagy does in fact play roles in regulating pollen tube growth guidance and male fertility in Arabidopsis thaliana. A detailed re-assessment of atg5 and atg7 mutants revealed greatly reduced autophagy activity in germinated pollens and the seed formation within siliques is partially abolished. Next, we demonstrated that both the pollen germination ratio and pollen tube length of the mutants decreased at the beginning of germination by time-lapse tracking of pollen germination in vitro and in vivo. Additionally, we observed occurrences of pollen tube twisting and stacking during their growth towards the ovules. Finally, we found abnormal pollen grains containing only a single sperm cell or an undivided generative nucleus. Collectively, these results indicate that ATG5- and ATG7-mediated autophagy is functionally involved in regulating pollen germination, tube growth guidance and sperm cell development in Arabidopsis thaliana.

plant biology↗