The transcription factor bZIP44 cooperates with MYB10 and MYB72 to regulate the response of Arabidopsis thaliana to iron deficiency stress.

Nicotianamine (NA) plays a crucial role in transporting metal ions, including iron (Fe), in plants; therefore, NICOTIANAMINE SYNTHASE (NAS) genes, which control NA synthesis, are tightly regulated at the transcriptional level. However, the transcriptional regulatory mechanisms of NAS genes require further investigations. In this study, we determined the role of bZIP44 in mediating plant response to Fe deficiency stress by conducting transformation experiments and assays. bZIP44 positively regulated the response of Arabidopsis to Fe deficiency stress by interacting with MYB10 and MYB72 to enhance their abilities to bind at NAS2 and NAS4 promoters, thereby increasing NAS2 and NAS4 transcriptional levels and promote NA synthesis. In summary, the transcription activities of bZIP44, MYB10, and MYB72 were induced in response to Fe deficiency stress, which enhanced the interaction between bZIP44 and MYB10 or MYB72 proteins, synergistically activated the transcriptional activity of NAS2 and NAS4, promoted NA synthesis, and improved Fe transport, thereby enhancing plant tolerance to Fe deficiency stress.

The transcription factor MYC1 interacts with FIT to negatively regulate iron homeostasis in Arabidopsis thaliana.

Iron (Fe) is an indispensable trace mineral element for the normal growth of plants, and it is involved in different biological processes; Fe shortage in plants can induce chlorosis and yield loss. The objective of this research is to identify novel genes that participated in the regulation of Fe-deficiency stress in Arabidopsis thaliana. A basic helix-loop-helix (bHLH) transcription factor (MYC1) was identified to be interacting with the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) using a yeast-two-hybrid assay. Transcript-level analysis showed that there was a decrease in MYC1 expression in Arabidopsis to cope with Fe-deficiency stress. Functional deficiency of MYC1 in Arabidopsis leads to an increase in Fe-deficiency tolerance and Fe-accumulation, whereas MYC1-overexpressing plants have an enhanced sensitivity to Fe-deficiency stress. Additionally, MYC1 inhibited the formation of FIT and bHLH38/39 heterodimers, which suppressed the expressed level for Fe acquisition genes FRO2 and IRT1 during Fe-deficiency stress. These results showed that MYC1 functions as a negative modulator of the Fe-deficiency stress response by inhibiting the formation of FIT and bHLH38/39 heterodimers, thereby suppressing the binding of FIT and bHLH38/39 heterodimers to the promoters of FRO2 and IRT1 to modulate Fe intake during Fe-deficiency stress. Overall, the findings of this study elucidated the role of MYC1 in coping with Fe-deficiency stress, and provided potential targets for the developing of crop varieties resistant to Fe-deficiency stress.

Linker histone variant HIS1-3 and WRKY1 oppositely regulate salt stress tolerance in Arabidopsis.

The salt overly sensitive (SOS) pathway plays an important role in plant salt stress; however, the transcriptional regulation of the genes in this pathway is unclear. In this study, we found that Linker histone variant HIS1-3 and WRKY1 oppositely regulate the salt stress response in Arabidopsis (Arabidopsis thaliana) through the transcriptional regulation of SOS genes. The expression of HIS1-3 was inhibited by salt stress, and the disruption of HIS1-3 resulted in enhanced salt tolerance. Conversely, the expression of WRKY1 was induced by salt stress, and the loss of WRKY1 function led to increased salt sensitivity. The expression of SOS1, SOS2, and SOS3 was repressed and induced by HIS1-3 and WRKY1, respectively, and HIS1-3 regulated the expression of SOS1 and SOS3 by occupying the WRKY1 binding sites on their promoters. Moreover, WRKY1 and HIS1-3 acted upstream of the SOS pathway. Together, our results indicate that HIS1-3 and WRKY1 oppositely modulate salt tolerance in Arabidopsis through transcriptional regulation of SOS genes.

Effects of Momordica saponin extract on alleviating fat accumulation in Caenorhabditis elegans.

Momordica saponins have diverse biological activities and are widely used to improve obesity. Here, we investigated the alleviation of fat accumulation and mechanism of action of the saponin-enriched ethanol extract from Momordica charantia (MSE) in Caenorhabditis elegans (C. elegans). First, MSE had a strong fat-reduction capacity in normal and high-fat worms. Second, MSE significantly increased the proportion of small lipid droplets and reduced the average particle size in ZXW618. Meanwhile, it improved lifespan and healthspan and physiological functions, such as age pigmentation and neuroprotection. Furthermore, MSE mediated fat reduction gets involved neither in energy intake nor in energy expenditure. Finally, MSE might down-regulate sbp-1 and nhr-49 via mdt-15, and up regulate age-1 via daf-2. And these targets genes together down-regulated the expression of fat-5, fat-6 and fat-7 to decrease fat accumulation. Our results provided new insights into the inhibition of fat accumulation and underlying mechanisms of Momordica saponins in C. elegans, which might be developed into a nutraceutical to ameliorate obesity.

[Statistics of internationally-issued English articles on ophthalmology by mainland Chinese authors during the past 6 years].

OBJECTIVE: To understand and to analyze the overall situation of ophthalmic research articles issued in English internationally by mainland Chinese authors during the past 6 years. METHODS: Using relevant retrieval words to search the articles from the PubMed, the largest database in biology and medical science in the world, and to conduct a statistical analysis. RESULTS: Three hundred and ninety two English ophthalmological articles by mainland Chinese researchers as the first author or first organization were published in 134 periodicals. Most of these organizations were medical universities (as well as their affiliated hospitals) and China Academy of Science. There were 23 journals which published more than 4 articles and there were 25 organizations issued more than 4 articles. CONCLUSIONS: During the past 6 years, there was a significant increase in the number of articles issued internationally by mainland Chinese authors, indicating an enormous progress in the field of ophthalmic research in mainland of China.

[Effects of all-trans retinoic acid on the rat Müller cell in vitro].

PURPOSE: To investigate the effects of various concentrations of all-trans retinoic acid (RA) on the rat Müller cells in vitro. METHODS: A rat Müller cell line was used in this study. Rat Müller cells were cultured with varying levels of RA for 24 h to 48 h. We examined cellular morphology under phase contrast microscope, cell proliferation using MTT assay, viable cell numbers by hemocytometer counting and cell apoptosis with flow cytometry. RESULTS: At lower concentration (< 0.1 microM), RA didn't change the cell's appearance and didn't inhibit the cell proliferation (P > 0.05). However, at higher concentration (1 microM, 10 microM, 100 microM), RA could inhibit the proliferation of Müller cells accompanied with morphological changes in a time- and dose-dependent manner. Furthermore, different concentration of RA (5 microM, 10 microM, 20 microM) could induce cell apoptosis. When using 20 microM RA to treat cells for 48 h, a significant decrease in cell numbers and an obvious increment of apoptotic cells were observed. The percentage of apoptotic cell was (35.87 +/- 7.40)% (P < 0.01, vs. control). CONCLUSIONS: RA can inhibit the proliferation and induce the apoptosis of müller cells in a time- and dose-dependent manner.