Study on the Interactions of Cyclins with CDKs Involved in Auxin Signal during Leaf Development by WGCNA in Populus alba.

Cell division plays an indispensable role in leaf morphogenesis, which is regulated via the complexes formed by cyclin and cyclin-dependent kinase (CDK). In this study, gene family analysis, exogenous auxin stimulation, RNA-seq and WGCNA analysis were all used to investigate the molecular mechanisms by which cell-cycle-related factors participated in the auxin signaling pathway on leaf morphogenesis. Sixty-three cyclin members and seventeen CDK members in Populus alba were identified and systematically analyzed. During the evolution, WGD was the main reason that resulted in the expansion of cyclin and CDK genes. Firstly, after a short time treating with auxin to matured leaves of seedlings, genes related to cell division including GRF and ARGOS were both upregulated to restart the transition of cells from G1-to-S phase. Secondly, with three days of continuous auxin stimulation to leaves at different developmental stages, leaves area variation, transcriptomes and hormones were analyzed. By PCA, PCoA and WGCNA analyses, the turquoise module was both positively related to leaf development and auxin. Based on the co-expression analysis and Y2H experiment, PoalbCYCD1;4, PoalbCYCD3;3 and PoalbCYCD3;5 were supposed to interact with PoalbCDKA;1, which could be the trigger to promote the G1-to-S phase transition. The ARF transcription factor might play the key role of connecting the auxin signaling pathway and cell division in leaf morphogenesis by affecting CYC-CDK complexes.

Mechanism of electron multiplication due to charging for a SiO2 sample with a buried microstructure in SEM: A simulation analysis.

This study investigates the mechanism of electron redistribution and multiplication for a SiO2 sample with a buried structure in scanning electron microscopy by numerical simulation. The simulation involved electron scattering and internal charge transport in the sample, the tracking of emitted secondary electrons (SEs), and the generation of tertiary electrons (TEs) produced by returned SEs due to charging of the sample. The results show that a buried grounded structure causes a non-uniform distribution of surface potential, and an electric field above the surface. As a result, although the number of escaped SEs above the margin of the buried structure decreases, the number of generated TEs increases more, leading to a final current of electrons that include escaped SEs and increased TEs. This multiplication of SEs might make a crucial contribution to the abnormal negative-charging contrast in SEM. During the electron beam irradiation, the variation in the number of total escaped electrons presents an obvious increase after an initial slight decrease, which corresponded to the transient characteristics of gray levels in SEM images from dark to abnormally bright.

Effects of delayed puerarin treatment in long-term neurological outcomes of focal ischemic stroke in rats.

OBJECTIVE: The present study aimed at investigate the therapeutic effects of delayed puerarin treatment in neurological outcomes after middle cerebral artery occlusion (MCAO) in rats. MATERIALS AND METHODS: Male Wistar rats were subjected to MCAO for 120 min followed by reperfusion for 14 days. Puerarin (0, 50, 100, 200 mg/kg, intra-peritoneally) was administered at 24 h after stroke onset and repeated daily for 14 days. Neurological deficits were evaluated at 1, 4, 7, 14 days after stroke. Brain infarct volume and peri-infarct context vessel density were examined at 14 days after stroke. RESULTS: Puerarin significantly improved neurological functions up to 14 days after stroke and decreased the infarct volume with doses of 50 mg/kg and 100 mg/kg compared with saline controls. Puerarin treatment also significantly increased peri-infarct context vessel density at 14 days after stroke. CONCLUSIONS: Delayed treatment of puerarin initiated at 24 h after stroke is beneficial with improved long-term neurological outcomes and reduced infarction volume in focal ischemic stroke in rats. Enhanced vascular remodeling by puerarin might at least partially contribute to its beneficial effects.

Trichokonins from Trichoderma pseudokoningii SMF2 induce resistance against Gram-negative Pectobacterium carotovorum subsp. carotovorum in Chinese cabbage.

Peptaibols, mainly produced by Trichoderma, play a pivotal role in controlling plant disease caused by fungi, virus, and Gram-positive bacteria. In the current study, we evaluated the control effect of Trichokonins, antimicrobial peptaibols from Trichoderma pseudokoningii SMF2, on soft rot disease of Chinese cabbage caused by a Gram-negative bacterium Pectobacterium carotovorum subsp. carotovorum and analyzed the mechanism involved. Trichokonins treatment (0.3 mg L(-1) ) enhanced the resistance of Chinese cabbage against Pcc infection. However, Trichokonins could hardly inhibit the growth of Pcc in vitro, even at high concentration (500 mg L(-1) ). Therefore, the direct effect of Trichokonins on Pcc may not the main reason why Trichokonins could control soft rot of Chinese cabbage. Trichokonin treatment led to an obvious increase in the production of reactive oxygen species hydrogen peroxide and superoxide radical, a significant enhance of the activities of pathogenesis-related enzymes catalase, polyphenoloxidase and peroxidase, and upregulation of the expression of salicylic acid - responsive pathogenesis-related protein gene acidic PR-1a in Chinese cabbage. These results indicate that Trichokonins induce resistance in Chinese cabbage against Pcc infection through the activation of salicylic acid signaling pathway, which imply the potential of Trichoderma and peptaibols in controlling plant disease caused by Gram-negative bacteria.

Comparing intraspecific responses of 12 winter wheat cultivars to different doses of ultraviolet-B radiation.

In this study, intraspecific responses of 12 winter wheat cultivars to different doses of ultraviolet-B radiation (UV-B) were analyzed and compared. The results showed that the low UV-B dose of 3.24kJm(-2)d(-1) generally inhibited the plant height, but promoted the dry weight and photochemical reflectance index (PRI). The high UV-B dose of 5.40kJm(-2)d(-1) inhibited most of the indexes, especially plant height and fresh weight. Under the treatments of two UV-B doses, the response indexes (RIs) of plant height, dry weight, fresh weight, carotenoid, and anthocyanin were all significantly correlated with the cumulative stress response index (CSRI). The RIs of carotenoid and anthocyanin exhibited higher correlations with dry weight and fresh weight, indicating that these indexes were vital to UV-B tolerance. By comparing the correlations of the seven indexes between two doses of UV-B radiation, the responses of 12 cultivars' plant height and dry weight to different doses of UV-B were very significant (P<0.01). Thus, when comparing the UV-B tolerance of different winter wheat seedlings, no matter using high dose or low dose UV-B, the index of plant height should be concerned first and dry weight could be used secondarily. Among 12 winter wheat cultivars, Nongda 6081 exhibited significant resistance to two doses of UV-B radiation while others were variable. Differences in the accumulation of UV-absorbing compounds induced by UV-B in leaves may be the main and direct reason for the intraspecific differences between resistant and sensitive cultivars.