Arabidopsis SRPKII family proteins regulate flowering via phosphorylation of SR proteins and effects on gene expression and alternative splicing.

Alternative splicing of pre-mRNAs is crucial for plant growth and development. Serine/arginine-rich (SR) proteins are a conserved family of RNA-binding proteins that are critical for both constitutive and alternative splicing. However, how phosphorylation of SR proteins regulates gene transcription and alternative splicing during plant development is poorly understood. We found that the Arabidopsis thaliana L. SR protein-specific kinase II family proteins (SRPKIIs) play an important role in plant development, including flowering. SRPKIIs regulate the phosphorylation status of a subset of specific SR proteins, including SR45 and SC35, which subsequently mediates their subcellular localization. A phospho-dead SR45 mutant inhibits the assembly of the apoptosis-and splicing-associated protein complex and thereby upregulates the expression of FLOWERING LOCUS C (FLC) via epigenetic modification. The splicing efficiency of FLC introns was significantly increased in the shoot apex of the srpkii mutant. Transcriptomic analysis revealed that SRPKIIs regulate the alternative splicing of c. 400 genes, which largely overlap with those regulated by SR45 and SC35-SCL family proteins. In summary, we found that Arabidopsis SRPKIIs specifically affect the phosphorylation status of a subset SR proteins and regulate the expression and alternative splicing of FLC to control flowering time.

Dynamic Regulation of Lipid Droplet Biogenesis in Plant Cells and Proteins Involved in the Process.

Lipid droplets (LDs) are ubiquitous, dynamic organelles found in almost all organisms, including animals, protists, plants and prokaryotes. The cell biology of LDs, especially biogenesis, has attracted increasing attention in recent decades because of their important role in cellular lipid metabolism and other newly identified processes. Emerging evidence suggests that LD biogenesis is a highly coordinated and stepwise process in animals and yeasts, occurring at specific sites of the endoplasmic reticulum (ER) that are defined by both evolutionarily conserved and organism- and cell type-specific LD lipids and proteins. In plants, understanding of the mechanistic details of LD formation is elusive as many questions remain. In some ways LD biogenesis differs between plants and animals. Several homologous proteins involved in the regulation of animal LD formation in plants have been identified. We try to describe how these proteins are synthesized, transported to the ER and specifically targeted to LD, and how these proteins participate in the regulation of LD biogenesis. Here, we review current work on the molecular processes that control LD formation in plant cells and highlight the proteins that govern this process, hoping to provide useful clues for future research.

Ultrasound-guided adaptive photoacoustic tomography.

Image formation in photoacoustic tomography (PAT) is generally based on the assumption that biological tissues are acoustically homogeneous. However, this does not hold, especially when strongly heterogeneous tissues, such as bones and air cavities, are present. Tissue heterogeneity can cause acoustic reflection, refraction, and scattering at interfaces, which may create distortions and artifacts in final images. To mitigate this problem, we propose an adaptive photoacoustic (PA) image reconstruction method based on prior structural information of an acoustically heterogeneous region extracted from ultrasound images. The method works in three steps: acoustic heterogeneity identification via ultrasound imaging; acoustically heterogeneous region segmentation; and adaptive time-domain raw data truncation and image reconstruction. The data truncation is based on a variable cutoff time, which can be adaptively determined according to the relative position of a transducer and an acoustically heterogeneous region. Numerical and in vivo experimental imaging results of human fingers demonstrate that the proposed ultrasound-guided adaptive image reconstruction method can effectively suppress acoustic heterogeneity-induced artifacts and substantially improve image quality. This work provides a practical way to mitigate the influence of acoustic heterogeneity in PAT.

Full-Length Transcriptome Sequencing Reveals the Impact of Cold Stress on Alternative Splicing in Quinoa.

Quinoa is a cold-resistant and nutrient-rich crop. To decipher the cold stress response of quinoa, the full-length transcriptomes of the cold-resistant quinoa variety CRQ64 and the cold-sensitive quinoa variety CSQ5 were compared. We identified 55,389 novel isoforms and 6432 novel genes in these transcriptomes. Under cold stress, CRQ64 had more differentially expressed genes (DEGs) and differentially alternative splicing events compared to non-stress conditions than CSQ5. DEGs that were specifically present only in CRQ64 were significantly enriched in processes which contribute to osmoregulation and ROS homeostasis in plants, such as sucrose metabolism and phenylpropanoid biosynthesis. More genes with differential alternative splicing under cold stress were enriched in peroxidase functions in CRQ64. In total, 5988 transcription factors and 2956 long non-coding RNAs (LncRNAs) were detected in this dataset. Many of these had altered expression patterns under cold stress compared to non-stress conditions. Our transcriptome results demonstrate that CRQ64 undergoes a wider stress response than CSQ5 under cold stress. Our results improved the annotation of the quinoa genome and provide new insight into the mechanisms of cold resistance in quinoa.

Dissecting the Molecular Regulation of Natural Variation in Growth and Senescence of Two Eutrema salsugineum Ecotypes.

Salt cress (Eutrema salsugineum, aka Thellungiella salsuginea) is an extremophile and a close relative of Arabidopsis thaliana. To understand the mechanism of selection of complex traits under natural variation, we analyzed the physiological and proteomic differences between Shandong (SD) and Xinjiang (XJ) ecotypes. The SD ecotype has dark green leaves, short and flat leaves, and more conspicuous taproots, and the XJ ecotype had greater biomass and showed clear signs of senescence or leaf shedding with age. After 2-DE separation and ESI-MS/MS identification, between 25 and 28 differentially expressed protein spots were identified in shoots and roots, respectively. The proteins identified in shoots are mainly involved in cellular metabolic processes, stress responses, responses to abiotic stimuli, and aging responses, while those identified in roots are mainly involved in small-molecule metabolic processes, oxidation-reduction processes, and responses to abiotic stimuli. Our data revealed the evolutionary differences at the protein level between these two ecotypes. Namely, in the evolution of salt tolerance, the SD ecotype highly expressed some stress-related proteins to structurally adapt to the high salt environment in the Yellow River Delta, whereas the XJ ecotype utilizes the specialized energy metabolism to support this evolution of the short-lived xerophytes in the Xinjiang region.

[Analysis of ZEB2 gene variation in two patients with Mowat-Wilson syndrome].

OBJECTIVE: To identify pathogenic variants in two patients with suspected for Mowat-Wilson syndrome (MWS). METHODS: Genomic DNA was extracted from peripheral blood samples of the patients and his family members, and gene variants were analysis by Trio-whole exome sequences and copy number variation sequencing. RESULTS: Patient 1 was found to carried a de novo heterozygous c.2769C>A (p.Y923*) nonsense variant of ZEB2 gene. The variant was not found in his healthy parents and sister. Patient 2 carried a de novo heterozygous frameshift variant of the ZEB2 gene, namely c.315delC (p.A105Afs*3), which has not been previously reported. Both variants were predicted to be pathogenic and can lead to premature occurrence of stop codons. CONCLUSION: The heterozygous c.2769C>A (p.Y923*) and c.315delC (p.A105Afs*3) variants of the ZEB2 gene probably underlay the pathogenesis in the two patients. Gene testing has facilitated confirmation of the diagnosis and genetic counselling.

Switchable generation of a sub-200 fs dissipative soliton and a noise-like pulse in a normal-dispersion Tm-doped mode-locked fiber laser.

We report on the switchable generation of a dissipative soliton (DS) pulse and a noise-like pulse (NLP) in an all-fiberized Tm-doped fiber laser in the normal-dispersion region. Mode-locking operation is achieved through a nonlinear polarization rotation component, and the cavity dispersion is compensated using ultra-high numerical aperture (UHNA4) fiber that is easy to integrate and low in cost. At a pump threshold of 510 mW, DS operation can first be achieved without additional filter. The 3 dB spectrum bandwidth of the DS pulse is greater than 50 nm, and the duration of the de-chirped pulse is 193 fs. By increasing the pump power to 880 mW, the mode-locking state can evolve into NLP operation with proper cavity polarization state. The 3 dB spectrum bandwidth and duration of de-chirped coherence spike are 105.6 nm and 121 fs, respectively. Meanwhile, ultra-broadband NLP (over 150 nm considering 3 dB spectrum width) can also be observed with the appropriate cavity parameters. All the proposed pulse patterns present good capacity for achieving narrow pulse width and withstanding high pulse energy.

Analysis and evaluation of the performance between reciprocity and time delay in the atmospheric turbulence channel.

In order to better evaluate the relationship between reciprocity and time delay of the fiber receiving system in the atmospheric turbulence channel, a time-domain signal generation mathematical model is proposed for the first time. A numerical solution of Johnson SB probability density distribution (PDF) in time-domain is creatively given for evaluating the reciprocity of both communication ends, which relates to the normalized fluctuation variance of the light intensity and the Greenwood frequency. An experiment is then carried out for verifying the time-domain signal generation model and measuring reciprocity. It shows that the excellent fitting accuracy of Johnson SB PDF signal generation model is first experimentally verified. It also indicates that the system reciprocity is improved by 10% after eliminating the system time delay. Meanwhile, the relationship between time delay and reciprocity under different atmospheric environments are analyzed and the relationship between time delay and system reciprocity at different Greenwood frequencies are discussed. This work provides a time parameter reference for the design of adaptive system and free-space optical (FSO) communication system.

Self-organized structures of bound states in a 2 µm dispersion-managed mode-locked fiber laser.

We report on the experimental generation of various self-organized structures of bound states in a near zero-dispersion mode-locked fiber laser. When the pump power is fixed at 492 mW, appropriately adjusting polarization controllers, the switching of the cavity feedback results in the evolution from the single pulse to the dispersion-managed soliton (i.e., stretched-pulse) pair. With the increase of pump power, bound states composed of more than two pulses can also be observed. Our results of the self-organized structures might enlarge the data-carrying capacity of current fiber-optical communication systems and benefit the investigation of nonlinear dynamics of bound states in fiber lasers at 2 µm.

Observation of sub-400fs, wavelength-switchable stretched pulse and bound-state pulse in Tm-doped fiber laser.

We report on the experimental observation of wavelength-switchable stretched pulse and bound-state pulse in a dispersion-managed Tm-doped laser. At a pump power of 572 mW, a stretched pulse with a pulse duration of 389 fs can be first obtained at 1961 nm. By increasing the pump power and appropriately adjusting the cavity polarization state, the mode-locking wavelength can be switched from 1961 nm to 1980 nm caused by the birefringence filtering effect based on nonlinear polarization rotation, and the corresponding pulse duration is 371 fs. Meanwhile, loosely bound states of two pulses and three pules at 1980 nm can be observed with appropriate cavity parameters.

Free-space transmission system in a tunable simulated atmospheric turbulence channel using a high-repetition-rate broadband fiber laser.

We demonstrate free-space transmission based on a broadband fiber laser at 16 Gbit/s over a simulated atmospheric turbulence channel. The broadband laser pulse is part of a supercontinuum generated by a homemade picosecond laser based on Raman gain soliton compression pumping a segment of highly nonlinear fiber. The scintillation indices, eye patterns, and bit error rates of transmission based on the broadband laser and a narrow-linewidth laser are compared. The results show a 29.5% reduction in the scintillation index and sensitivity of -28.6 dBm at the forward error correction limit, which has a 2.9 dB improvement compared with the narrow-linewidth system. It is feasible to use broadband lasers as carriers combining optical time division multiplexing as a multiplexing method to improve the communication performance under weak atmospheric turbulent conditions.

The Arabidopsis catalase triple mutant reveals important roles of catalases and peroxisome-derived signaling in plant development.

Hydrogen peroxide (H2 O2 ) is generated in many metabolic processes. As a signaling molecule, H2 O2 plays important roles in plant growth and development, as well as environmental stress response. In Arabidopsis, there are three catalase genes, CAT1, CAT2, and CAT3. The encoded catalases are predominately peroxisomal proteins and are critical for scavenging H2 O2 . Since CAT1 and CAT3 are linked on chromosome 1, it has been almost impossible to generate cat1/3 and cat1/2/3 mutants by traditional genetic tools. In this study, we constructed cat1/3 double mutants and cat1/2/3 triple mutants by CRISPR/Cas9 to investigate the role of catalases. The cat1/2/3 triple mutants displayed severe redox disturbance and growth defects under physiological conditions compared with wild-type and the cat2/3 double mutants. Transcriptome analysis showed a more profound transcriptional response in the cat1/2/3 triple mutants compared to the cat2/3 mutants. These differentially expressed genes are involved in plant growth regulation as well as abiotic and biotic stress responses. In addition, expression of OXI1 (OXIDATIVE SIGNAL INDUCIBLE 1) and several MAPK cascade genes were changed dramatically in the catalase triple mutant, suggesting that H2 O2 produced in peroxisomes could serve as a peroxisomal retrograde signal.

Qualitative and quantitative analysis of major constituents from Dazhu Hongjingtian capsule by UPLC/Q-TOF-MS/MS combined with UPLC/QQQ-MS/MS.

In this work, a sensitive and efficient method was established and validated for qualitative and quantitative analysis of major bioactive constituents in Dazhu Hongjingtian capsule by liquid chromatography tandem mass spectrometry. A total of 32 compounds were tentatively identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Furthermore, 12 constituents, namely gallic acid, 3,4-dihydroxybenzoic acid, salidroside, p-coumaric acid-4-O-ß-d-glucopyranoside, bergeninum, 4-hydroxybenzoic acid, 4-hydroxyphenylacetic acid, syringate, 6''-O-galloylsalidroside, rhodiosin, rhodionin and kaempferol-7-O-α-l-rhamnoside, were simultaneously quantified by the developed ultra-performance liquid chromatography coupled with a triple quadrupole mass spectrometry method in 9 min. All of them were analyzed on an Agilent ZorBax SB-C18 column (3.0 × 100 mm, 1.8 µm) with linear gradient elution of methanol-0.1% formic acid water. The proposed method was applied to analyze three batches of samples with acceptable linearity (R, 0.9979-0.9997), precision (RSD, 1.3-4.7%), repeatability (RSD, 1.7-4.9%), stability (RSD, 2.2-4.9%) and recovery (RSD, 0.6-4.4%) of the 12 compounds. As a result, the analytical method possessing high throughput and sensitivity is suitable for the quality control of Dazhu Hongjingtian capsule.

[Optimization of extraction technology for salidroside, tyrosol, crenulatin and gallic acid in Rhodiolae Crenulatae Radix et Rhizoma with orthogonal test].

The extracting technology of salidroside, tyrosol, crenulatin and gallic acid from Rhodiolae Crenulatae Radix et Rhizoma was optimized. With extraction rate of salidroside, tyrosol, crenulatin and gallic acid as indexes, orthogonal test was used to evaluate effect of 4 factors on extracting technology, including concentration of solvent, the dosage of solvent, duration of extraction, and frequency of extraction. The results showed that, the best extracting technology was to extract in 70% alcohol with 8 times the weight of herbal medicine for 2 times, with 3 hours once. High extraction rate of salidroside, tyrosol, crenulatin and gallic acid were obtained with the present technology. The extracting technology was stable and feasible with high extraction rate of four compounds from Rhodiolae Crenulatae Radix et Rhizoma, it was suitable for industrial production.

[Simultaneously preparation of grams of high purity tyrosol, crenulatin and salidroside from Rhodiola crenulata].

Tyrosol, crenulatin and salidroside are the main active constituents of Rhodiola crenulata, with extensive pharmacological activities. In the study, grams of high purity tyrosol, crenulatin and salidroside were simultaneously separated from R. crenulata by the first time. Firstly, R. crenulata was extracted by 70% alcohol. Then, with the yields of three compounds as the index, the macroporous resin was optimized. At last, grams of high purity tyrosol, crenulatin and salidroside were isolated by D-101 macroporousresin, purified by column chromatography. Detected by HPLC, the purity of three compounds were higher than 98%. This method has the advantages of simple process and operation, less dosage of organic solvent, highly yield and reproducibility, suitable for the simultaneously preparation of tyrosol, crenulatin and salidroside.

[Preparation of baicalein using thermophilic and sugar-tolerant beta-glucosidase].

The reaction conditions of baicalin hydrolyzed into baicalein by a kind of thermophilic and sugar-tolerant beta-glucosidase were studied in this paper. The beta-glucosidase could catalyze baicalin into baicalein well in the acetic acid-sodium acetate buffer. The optimal enzyme activity was at 85 degrees C and pH 5.5. The enzyme was stable at the temperature less than 85 degrees C and pH range of 5-7.5. The maximum reaction rate V. and michaelis constant K. were 0.41 mmol x L(-1) x min(-1) and 3.31 mmol x L(-1) respectively. Different metal ions had different effects on the activity of enzyme. Na+ existing in acetic acid-sodium acetate buffer had an activation effect on enzyme. The enzyme activity was enhanced by the concentrations of glucose below 0.6 mol x L(-1), and was gradually inhibited when monosaccharide concentration was over 0.6 mol x L(-1). When the monosaccharide concentration reached 1.2 mol x L(-1), the inhibition rate of enzyme activity was about 50%, which showed good glucose tolerance. The good reaction conditions through the experiment have been determined as follows, the substrate: enzyme dose was 1 g: 0.2 mL, acetic acid-sodium acetate buffer pH 5.5, reaction temperature 85 degrees C, reaction time 10 h, and the enzymatic hydrolyzation ratio could reach 97%.

[Advance in research on chemical constituents from Notopterygii Rhizoma et Radix].

This paper summarized the recent 30 years research progress of the chemical constituents from Notopterygii Rhizoma et Radix. The chemical constituents from Notopterygii Rhizoma et Radix mainly consist of coumarins, polyene-polyacetylenes, sesquiterpenes, phenolic acids, while steroids and flavonoids were less reported. All constituents were confirmed and corrected through SciFinder. We also checked the Chinese name and English name and listed the CAS number of each compound. It can provide some guidelines for the research, development and utilization of Notopterygii Rhizoma et Radix in the future. Whether there is columbianin in the Notopterygii Rhizoma et Radix need to be further researched.

[Application of molecularly imprinted technology for separation of PGG from Guizhi Fuling capsule].

1,2,3,4,6-penta-O-galloyl-D-glucose (PGG) is one of the main active compounds of Guizhi Fuling capsule. Molecularly imprinted polymers (MIP) have high affinity toward template molecules synthesized by molecularly imprinted technology for its specific combined sites, which can overcome the shortcoming of traditional separation methods, such as complex operation, low efficiency, using large quantity of solvent and environmental pollution. In this paper, surface molecularly imprinted polymer (SMIP) was prepared by surface imprinting with PGG as the template molecule. Its adsorption capacity was measured by the scatchard equation. The separation of PGG from Guizhi Fuling capsule at preparatived scale was achieved with molecularly imprinted polymer as stationary phase and the purity was 90.2% by HPLC. This method can be used to prepare PGG from Guizhi Fuling capsule with large capacity and is easy to operate. It provides a new method for efficient separation and purification for other natural products.

[Anti-complementary phenolic acids from Lonicera japonica].

OBJECTIVE: To study the anti-complementary phenolic acids from Lonicera japonica. METHOD: The anti-complementary activity-directed isolation was carried out with the hemolysis test as guide. All isolation was evaluated for their in vitro anti-complementary activities. The structures were identified by various spectroscopic data including ESI-MS, 1H-NMR, 13C-NMR data. RESULT: Fourteen compounds were isolated from the EtOAc fraction of L. japonica extracts, including 8 phenolic acids: 5-O-caffeoylquinic acid (1), chlorogenic (2), 4-O-caffeoylquinic acid (3), 3,5-di-O-caffeoylquinic acid (4), 4,5-di-O-caffeoylquinic acid (5), 3,4-di-O-caffeoylquinic acid (6), caffeic acid (7) and methyl caffeate acid (8); 3 iridoids: secologanoside (9), sweroside (10) and secoxyloganin (11); and 3 flavonoids: luteolin (12), quercetin (13) and kaempferol (14). Compounds 1-9 and 11-14 showed anti-complementary activity in different extents and 3,5-di-O-caffeoylquinic acid (4) exhibited the most significant activity against the classical pathway. CONCLUSION: Compound 14 is obtained from this plant for the first time, phenolic acids are the main anti-complementary constituents of L. japonica and 3,5-di-O-caffeoylquinic acid(4) is a potential complement inhibitor with strong activity, which worthy to be studied further in the future.

Four new triterpenoids isolated from the resin of Garcinia hanburyi.

Four new triterpenoids, 2-O-acetyl-3-O-(4'-O-acetyl)-α-l-arabinopyranosylmaslinic acid (1), 2-O-acetyl-3-O-(3'-O-acetyl)-α-l-arabinopyranosylmaslinic acid (2), 2-O-acetyl-3-O-(3',4'-O-diacetyl)-α-l-arabinopyranosylmaslinic acid (3), and 3-O-(3'-O-acetyl)-α-l-arabinopyranosyloleanolic acid (4), together with six known triterpenoids, 3-O-(4'-O-acetyl)-α-l-arabinopyranosyloleanolic acid (5), maslinic acid (6), 2-O-acetylmaslinic acid (7), 3-O-acetylmaslinic acid (8), betulinic acid (9), and 2α-hydroxy-3ß-O-acetylbetulinic acid (10), were isolated from the EtOAc extract of Garcinia hanburyi resin. Their structures were elucidated by analysis of the spectroscopic data and chemical methods.