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Plants use several pathways to synthesize phosphatidylcholine (PC), the major phospholipid of eukaryotic cells. PC has important structural and signaling roles. One pathway plants use for synthesis is the phospho-base methylation pathway, which forms the head-group phosphocholine through the triple methylation of phosphoethanolamine (PEA) catalyzed by phosphoethanolamine N-methyltransferases (PEAMTs). Our understanding of that pathway and its physiological importance remains limited. We recently reported that disruption of Arabidopsis thaliana PEAMT1/NMT1 and PEAMT3/NMT3 induces severe PC deficiency leading to dwarfism and impaired development. However, the double nmt1 nmt3 knock-out mutant is viable. Here, we show that this is enabled by residual PEAMT activity through a third family member, NMT2. The triple nmt1 nmt2 nmt3 knock-out mutant cannot synthesize PC from PEA and is lethal. This shows that, unlike mammals and yeast, Arabidopsis cannot form PC from phosphatidyl ethanolamine (PE), and demonstrates that methylation of PEA is the sole, and vital, entry point to PC synthesis. We further show that Arabidopsis has evolved an expanded family of four nonredundant PEAMTs through gene duplication and alternate use of the NMT2 promoter. NMT2 encodes two PEAMT variants, which greatly differ in their ability to perform the initial phospho-base methylation of PEA. Five amino acids at the N terminus of PEAMTs are shown to each be critical for the catalysis of that step committing to PC synthesis. As a whole, these findings open new avenues for enzymatic engineering and the exploration of ways to better tune phosphocholine and PC synthesis to environmental conditions for improved plant performance. [ABSTRACT FROM AUTHOR]

Phosphatidylcholine (PC) is a major membrane phospholipid and a precursor for major signaling molecules. Understanding its synthesis is important for improving plant growth, nutritional value, and resistance to stress. PC synthesis is complex, involving several interconnected pathways, one of which proceeds from serine-derived phosphoethanolamine to form phosphocholine through three sequential phospho-base methylations catalyzed by phosphoethanolamine N-methyltransferases (PEAMTs). The contribution of this pathway to the production of PC and plant growth has been a matter of some debate. Although a handful of individual PEAMTs have been described, there has not been any in planta investigation of a PEAMT family. Here, we provide a comparative functional analysis of two Arabidopsis (Arabidopsis thaliana) PEAMTs, NMT1 and the little known NMT3. Analysis of loss-of-function mutants demonstrates that NMT1 and NMT3 synergistically regulate PC homeostasis, phase transition at the shoot apex, coordinated organ development, and fertility through overlapping but also specific functions. The nmt1 nmt3 double mutant shows extensive sterility, drastically reduced PC concentrations, and altered lipid profiles. These findings demonstrate that the phospho-base methylation pathway makes a major contribution to PC synthesis in Arabidopsis and that NMT1 and NMT3 play major roles in its catalysis and the regulation of PC homeostasis as well as in plant growth and reproduction. [ABSTRACT FROM AUTHOR]

Ras homolog gene family, member A (RhoA) has been reported as essential to the invasion process and aggressiveness of numerous cancers. However, there are only sparse data on the expression and activity of RhoA in clinically localised prostate cancer. In numerous cancers, tumour cells at the invasive front demonstrate more aggressive behaviour in comparison with the cells in the central regions. In the present study, the expression and activity of RhoA was evaluated in 34 paraffin-embedded and 20 frozen prostate tissue specimens obtained from 45 patients treated with radical prostatectomy for clinically localised cancer. The expression patterns of RhoA were assessed by immunohistochemical staining and western blotting. Additional comparisons were performed between the tumour centre, tumour front and distant peritumoural tissue. RhoA activity was assessed by G-LISA. Associations between RhoA expression and the clinical features and outcome of the patients were also analysed. The present study found an increasing gradient of expression from the centre to the periphery of index tumour foci. RhoA expression was significantly increased at the tumour front compared to the tumour centre, which was determined using immunohistochemistry (P=0.001). Increased RhoA expression was associated with poor tumour differentiation in the tumour front (P=0.044) and tumour centre (P=0.039). Subsequent to a median follow-up period of 52 months, the rate of prostate-specific antigen (PSA) relapse was increased in patients with higher RhoA expression at the tumour front when compared with patients with lower RhoA expression (62.5 vs. 35.0%), although the difference was not significant (P=0.09). There was no association between RhoA expression and the PSA level or pathological stage in the present study. In conclusion, RhoA expression was increased at the tumour front and was associated with poor tumour differentiation in the tumour front and tumour centre, indicating the potential role of RhoA in prostate cancer. RhoA expression may also act as a prognostic factor in prostate cancer. The present data provide a foundation for novel therapeutic approaches by targeting RhoA in prostate cancer. [ABSTRACT FROM AUTHOR]

Prostate cancer (PCa) remains a major cause of mortality among males in western countries, with little change in mortality rates observed over the past 25 years. Despite recent advances in therapy, treatment options for metastatic castration-resistant disease remain limited. In terms of chemotherapy, only the combination of docetaxel and prednisone has been shown to improve survival in these patients, but duration of response to therapy is short. There is a continuing unmet need for new systemic interventions that act either alone or synergistically with chemotherapy in patients with progressive PCa. Angiogenesis plays a critical role in tumor growth and metastasis in PCa. Several strategies have been used to target angiogenesis; however, it is becoming increasingly apparent that current anti-angiogenic therapies frequently achieve only modest effects in clinical settings. The RhoA/Rho kinase (ROCK) pathway plays a crucial role in the process of angiogenesis in PCa, and studies have demonstrated that ROCK inhibitors decrease VEGF-induced angiogenesis and tumor cell growth. However, further research is required to fully elucidate the molecular mechanisms involved in this pathway, and the potential value of modulating these mechanisms in the treatment of PCa. This study reviews the current understanding of the role of the RhoA/ROCK pathway in the process of angiogenesis in PCa, and the potential of this pathway as a therapeutic target in the future. [ABSTRACT FROM AUTHOR]

2-(2'-Hydroxyphenyi)benzoxazole (HBO) derivatives represent an important class of luminescent materials, as they can undergo excited state intramolecular proton transfer (ES1PT). The material's ESIPT properties are dependent on the ratio of two different retainers, whose interconversion is poorly understood. By using HBO derivative 4, the rotational energy barrier of 2- (2',6'-hydroxyphenyl)benzoxazole is determined to be 10.5 kcal/mol by variable-temperature NMR. Although a HBO derivative typically exhibits two rotamers with O--H--O (e.g., la) and N--H--O bonding (e.g., lb), correlation of NMR with fluorescence data reveals that the retainer with N--H--O bonding is predominant in the solution. [ABSTRACT FROM AUTHOR]

Arsenic is a ubiquitous environmental poison that inhibits root elongation and seed germination to a variable extent depending on the plant species. To understand the molecular mechanisms of arsenic resistance, a genetic screen was developed to isolate arsenate overly sensitive (aos) mutants from an activation-tagged Arabidopsis (Arabidopsis thaliana) population. Three aos mutants were isolated, and the phenotype of each was demonstrated to be due to an identical disruption of plastidial LIPOAMIDE DEHYDROGENASE1 (ptLPD1), a gene that encodes one of the two E3 isoforms found in the plastidial pyruvate dehydrogenase complex. In the presence of arsenate, ptlpd1-1 plants exhibited reduced root and shoot growth and enhanced anthocyanin accumulation compared with wild-type plants. The ptlpd1-1 plants accumulated the same amount of arsenic as wild-type plants, indicating that the aos phenotype was not due to increased arsenate in the tissues but to an increase in time innate sensitivity to the poison. Interestingly, a ptlpd1-4 knockdown allele produced a partial aos phenotype. Two loss-of-function alleles of ptLPD2 in Arabidopsis also caused elevated arsenate sensitivity, but the sensitivity was less pronounced than for the ptlpd1 mutants. Moreover, both the ptlpd1 and ptlpd2 mutants were more sensitive to arsenite than wild-type plants, and time LPD activity in isolated chloroplasts from wild-type plants was sensitive to arsenite but not arsenate. These findings show that the ptLPD isoforms are critical in vivo determinants of arsenite-mediated arsenic sensitivity in Arabidopsis and possible strategic targets for increasing arsenic tolerance. [ABSTRACT FROM AUTHOR]

The western population of the red‐crowned crane Grus japonensis in mainland China has been decreasing in the past few decades and wild population enhancement programmes have been launched in this country. First, 14 captive‐bred red‐crowned cranes were released into the core area of Yancheng National Nature Reserve for Rare Birds (YNNR), one of the most important wintering areas of this species, in 2013 (seven individuals) and 2015 (seven individuals) and then 8 more captive‐bred cranes were released into YNNR from February 2022 to February 2023. We used satellite positioning and drone monitoring to study the status of released cranes. The results showed that two individuals (No. BJZ001 and BJZ008) from the first group of released cranes were found breeding in 6 of 7 years in the YNNR from 2017 to 2023. Three individuals (No. WNNR022, WNNR025 and WNNR026) from the second group of released cranes were recorded breeding in YNNR in 2023. All released cranes lived in the YNNR year round and did not migrate with wild cranes. Raccoon dogs, Nyctereutes procyonoides, were first recorded as red‐crowned crane nest predators in the YNNR. Although these released cranes breed successfully in the YNNR, nestlings might face the threat of predators in non‐traditional breeding areas. Further research is needed to determine whether offsprings of released individuals migrate with wild cranes and if breeding in their original wintering grounds is truly beneficial for population growth. [ABSTRACT FROM AUTHOR]

The western population of the red‐crowned crane Grus japonensis in mainland China has been decreasing in the past few decades and wild population enhancement programmes have been launched in this country. First, 14 captive‐bred red‐crowned cranes were released into the core area of Yancheng National Nature Reserve for Rare Birds (YNNR), one of the most important wintering areas of this species, in 2013 (seven individuals) and 2015 (seven individuals) and then 8 more captive‐bred cranes were released into YNNR from February 2022 to February 2023. We used satellite positioning and drone monitoring to study the status of released cranes. The results showed that two individuals (No. BJZ001 and BJZ008) from the first group of released cranes were found breeding in 6 of 7 years in the YNNR from 2017 to 2023. Three individuals (No. WNNR022, WNNR025 and WNNR026) from the second group of released cranes were recorded breeding in YNNR in 2023. All released cranes lived in the YNNR year round and did not migrate with wild cranes. Raccoon dogs, Nyctereutes procyonoides, were first recorded as red‐crowned crane nest predators in the YNNR. Although these released cranes breed successfully in the YNNR, nestlings might face the threat of predators in non‐traditional breeding areas. Further research is needed to determine whether offsprings of released individuals migrate with wild cranes and if breeding in their original wintering grounds is truly beneficial for population growth. [ABSTRACT FROM AUTHOR]

The rapid urbanization and economic development of China has led to a dramatic increase in nitrogen oxide (NO2) emissions, causing serious atmospheric nitrogen pollution and relatively high levels of nitrogen deposition. However, despite the importance of nitrogen deposition, dry deposition processes in forested areas are still insufficiently represented in current global and regional atmospheric chemistry models, which constrains our understanding and prediction of spatial and temporal patterns of nitrogen transport in forest ecosystems in South China. The offline 1-D community Noah land surface model with multi-parameterization options (Noah-MP) is coupled with the WRF-Chem dry deposition module (WDDM) and is applied to further understand and identify the key processes that affect forest canopy dry deposition. The canopy stomatal resistance mechanism and the nitrogen-limitings scheme for photosynthesis in Noah-MP-WDDM are modified to improve the simulation of reactive nitrogen oxide dry deposition velocity. This study finds that the combined improved stomatal resistance mechanism and nitrogen-limitings scheme for photosynthesis (BN-23) agrees better with the observed NO2 dry deposition velocity, with mean bias reduced by 50.1%, respectively. At the same time, by comparing the different mechanisms of the two processes of canopy stoma resistance and leaf nitrogen-limiting factors, this study also finds that the diurnal changes in dry deposition velocity simulated by each regional model present four sets of distributions. This is mainly due to the different ways that each integrated mechanism handles the opening and closing of stomata at noon and the way the nitrogen-limiting factor acts. [ABSTRACT FROM AUTHOR]

Complex power electronic conversion devices, most of which have high transmission performance, are important power conversion units in modern aircraft power systems. However, these devices can also affect the stability of the aircraft power system more and more prominent due to their dynamic and nonlinear characteristics. To analyze the stability of aircraft power systems in a simple, accurate and comprehensive way, this paper develops a unified large signal model of aircraft power systems. In this paper, first the Lyapunov linearization method and the mixed potential theory are employed to analyze small signal and large signal stability, respectively, and then a unified stability criterion is proposed to estimate small and large signal stability problems. Simulation results show that the unified large signal model of aircraft power systems presented in this paper can be used to analyze the stability problem of aircraft power systems in an accurate and comprehensive way. Furthermore, with simplicity, universality and structural uniformity, the unified large signal model lays a good foundation for the optimal design of aircraft power systems. [ABSTRACT FROM AUTHOR]

Alterations of mitochondrial-encoded subunits of the FoF1-ATP synthase are frequently associated with cytoplasmic male sterility (CMS) in plants; however, little is known about the relationship of the nuclear encoded subunits of this enzyme with CMS. In the present study, the full cDNA of the gene TaFAd that encodes the putative FAd subunit of the FoF1-ATP synthase was isolated from the wheat (Triticum aestivum) fertility restorer ‘2114’ for timopheevii cytoplasm-based CMS. The deduced 238 amino acid polypeptide is highly similar to its counterparts in dicots and other monocots but has low homology to its mammalian equivalents. TaFAd is a single copy gene in wheat and maps to the short arm of the group 6 chromosomes. Transient expression of the TaFAd–GFP fusion in onion epidermal cells demonstrated TaFAd's mitochondrial location. TaFAd was expressed abundantly in stem, leaf, anther, and ovary tissues of 2114. Nevertheless, its expression was repressed in anthers of CMS plants with timopheevii cytoplasm. Genic male sterility did not affect its expression in anthers. The expression of the nuclear gene encoding the 20 kDa subunit of Fo was down-regulated in a manner similar to TaFAd in the T-CMS anthers while that of genes encoding the 6 kDa subunit of Fo and the γ subunit of F1 was unaffected. These observations implied that TaFAd is under mitochondrial retrograde regulation in the anthers of CMS plants with timopheevii cytoplasm. [ABSTRACT FROM PUBLISHER]