Hypothetical chloroplast reading frame 51 encodes a photosystem I assembly factor in cyanobacteria.

Hypothetical chloroplast open reading frames (ycfs) are putative genes in the plastid genomes of photosynthetic eukaryotes. Many ycfs are also conserved in the genomes of cyanobacteria, the presumptive ancestors of present-day chloroplasts. The functions of many ycfs are still unknown. Here, we generated knock-out mutants for ycf51 (sll1702) in the cyanobacterium Synechocystis sp. PCC 6803. The mutants showed reduced photoautotrophic growth due to impaired electron transport between photosystem II (PSII) and PSI. This phenotype results from greatly reduced PSI content in the ycf51 mutant. The ycf51 disruption had little effect on the transcription of genes encoding photosynthetic complex components and the stabilization of the PSI complex. In vitro and in vivo analyses demonstrated that Ycf51 cooperates with PSI assembly factor Ycf3 to mediate PSI assembly. Furthermore, Ycf51 interacts with the PSI subunit PsaC. Together with its specific localization in the thylakoid membrane and the stromal exposure of its hydrophilic region, our data suggest that Ycf51 is involved in PSI complex assembly. Ycf51 is conserved in all sequenced cyanobacteria, including the earliest branching cyanobacteria of the Gloeobacter genus, and is also present in the plastid genomes of glaucophytes. However, Ycf51 has been lost from other photosynthetic eukaryotic lineages. Thus, Ycf51 is a PSI assembly factor that has been functionally replaced during the evolution of oxygenic photosynthetic eukaryotes.

Coevolution of tandemly repeated hlips and RpaB-like transcriptional factor confers desiccation tolerance to subaerial Nostoc species.

Desert-inhabiting cyanobacteria can tolerate extreme desiccation and quickly revive after rehydration. The regulatory mechanisms that enable their vegetative cells to resurrect upon rehydration are poorly understood. In this study, we identified a single gene family of high light-inducible proteins (Hlips) with dramatic expansion in the Nostoc flagelliforme genome and found an intriguingly special convergence formed through four tandem gene duplication. The emerged four independent hlip genes form a gene cluster (hlips-cluster) and respond to dehydration positively. The gene mutants in N. flagelliforme were successfully generated by using gene-editing technology. Phenotypic analysis showed that the desiccation tolerance of hlips-cluster-deleted mutant decreased significantly due to impaired photosystem II repair, whereas heterologous expression of hlips-cluster from N. flagelliforme enhanced desiccation tolerance in Nostoc sp. PCC 7120. Furthermore, a transcription factor Hrf1 (hlips-cluster repressor factor 1) was identified and shown to coordinately regulate the expression of hlips-cluster and desiccation-induced psbAs. Hrf1 acts as a negative regulator for the adaptation of N. flagelliforme to the harsh desert environment. Phylogenetic analysis revealed that most species in the Nostoc genus possess both tandemly repeated Hlips and Hrf1. Our results suggest convergent evolution of desiccation tolerance through the coevolution of tandem Hlips duplication and Hrf1 in subaerial Nostoc species, providing insights into the mechanism of desiccation tolerance in photosynthetic organisms.

[Non-targeted metabolomics of spleen and liver metabolism in mice treated with Pruni Semen processed with different methods].

Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was employed to investigate the impacts of Pruni Semen processed with different methods(raw and fried) on the liver and spleen metabolism in mice. A total of 24 male mice were randomly assigned to three groups: raw Pruni Semen group, fried Pruni Semen group, and control(deionized water) group. Mice in the three groups were orally administrated with 0.01 g·mL~(-1) Pruni Semen decoction or deionized water for one week. After that, the liver and spleen tissues were collected, and liquid chromatography-mass spectrometry(LC-MS)-based metabolomic analysis was carried out to investigate the impact of Pruni Semen on the liver and spleen metabolism in mice. Compared with thte control group, the raw Pruni Semen group showed up-regulation of 11 metabolites and down-regulation of 57 metabolites in the spleen(P<0.05), as well as up-regulation of 15 metabolites and down-regulation of 58 metabolites in the liver(P<0.05). The fried Pruni Semen group showed up-regulation of 31 metabolites and down-regulation of 10 metabolites in the spleen(P<0.05), along with up-regulation of 26 metabolites and down-regulation of 61 metabolites in the liver(P<0.05). The differential metabolites identified in the raw Pruni Semen group were primarily associated with alanine, aspartate, and glutamate metabolism, purine metabolism, amino sugar and nucleotide sugar metabolism, and D-glutamine and D-glutamate metabolism. The differential metabolites identified in the fried Pruni Semen group predominantly involved riboflavin metabolism, amino sugar and nucleotide sugar metabolism, purine metabolism, alanine, aspartate, and glutamate metabolism, D-glutamine and D-glutamate metabolism, and glutathione metabolism. The findings suggest that both raw and fried Pruni Semen have the potential to modulate the metabolism of the liver and spleen in mice by influencing the glutamine and glutamate metabolism.

Expansion of bilin-based red light sensors in the subaerial desert cyanobacterium Nostoc flagelliforme.

Light is the crucial environmental signal for desiccation-tolerant cyanobacteria to activate photosynthesis and prepare for desiccation at dawn. However, the photobiological characteristics of desert cyanobacteria adaptation to one of the harshest habitats on Earth remain unresolved. In this study, we surveyed the genome of a subaerial desert cyanobacterium Nostoc flagelliforme and identified two phytochromes and seven cyanobacteriochromes (CBCRs) with one or more bilin-binding GAF (cGMP phosphodiesterase/adenylyl cyclase/FhlA) domains. Biochemical and spectroscopic analyses of 69 purified GAF-containing proteins from recombinant phycocyanobilin (PCB), biliverdin or phycoerythrobilin-producing Escherichia coli indicated that nine of these proteins bind chromophores. Further investigation revealed that 11 GAFs form covalent adducts responsive to near-UV and visible light: eight GAFs contained PCB chromophores, three GAFs contained biliverdin chromophores and one contained the PCB isomer, phycoviolobilin. Interestingly, COO91_03972 is the first-ever reported GAF-only CBCR capable of sensing five wavelengths of light. Bioinformatics and biochemical analyses revealed that residue P132 of COO91_03972 is essential for chromophore binding to dual-cysteine CBCRs. Furthermore, the complement of N. flagelliforme CBCRs is enriched in red light sensors. We hypothesize that these sensors are critical for the acclimatization of N. flagelliforme to weak light environments at dawn.

Dehydration-Induced DnaK2 Chaperone Is Involved in PSII Repair of a Desiccation-Tolerant Cyanobacterium.

Maintaining the structural integrity of the photosynthetic apparatus during dehydration is critical for effective recovery of photosynthetic activity upon rehydration in a variety of desiccation-tolerant plants, but the underlying molecular mechanism is largely unclear. The subaerial cyanobacterium Nostoc flagelliforme can survive extreme dehydration conditions and quickly recovers its photosynthetic activity upon rehydration. In this study, we found that the expression of the molecular chaperone NfDnaK2 was substantially induced by dehydration, and NfDnaK2 proteins were primarily localized in the thylakoid membrane. NfDnaJ9 was identified to be the cochaperone partner of NfDnaK2, and their encoding genes shared similar transcriptional responses to dehydration. NfDnaJ9 interacted with the NfFtsH2 protease involved in the degradation of damaged D1 protein. Heterologous expression of NfdnaK2 enhanced PSII repair and drought tolerance in transgenic Nostoc sp. PCC 7120. Furthermore, the nitrate reduction (NarL)/nitrogen fixation (FixJ) family transcription factors response regulator (NfRre1) and photosynthetic electron transport-dependent regulator (NfPedR) were identified as putative positive regulators capable of binding to the promoter region of NfdnaK2 and they may mediate dehydration-induced expression of NfdnaK2 in N. flagelliforme Our findings provide novel insights into the molecular mechanism of desiccation tolerance in some xerotolerant microorganisms, which could facilitate future synthetic approaches to the creation of extremophiles in microorganisms and plants.

Copper(II)-Catalyzed Direct C-H (Hetero)arylation at the C3 Position of Indoles Assisted by a Removable N,N-Bidentate Auxiliary Moiety.

The regioselective arylation of inert C3-H bonds in indoles reacting with arylboronates via effective copper-mediated catalysis with the aid of a facile and removable 2-pyridinylisopropyl (PIP) group without ligand participation is reported. This newly established method features high compatibility with diverse functional groups between coupling partners, including both indole substrates and arylboron reagents, consequentially leading to operational simplicity and providing access to generate the desired arylated products in good to excellent yields of up to 97%. Synthetically, the PIP-derived amide moiety could subsequently be readily removed under mild reaction conditions to produce useful indole carboxylic acids for further transformation.

Synthesis of indolo[2,1-α]isoquinoline derivatives via metal-free radical cascade cyclization.

In the present studies, we describe a convenient and efficient protocol for the synthesis of the indolo[2,1-α]isoquinoline core structure through the reaction of 2-aryl-N-acryloyl indoles and aryl or alkyl α-keto acids under air environment in four hours. The developed approach features broad substrate scope and good functional group tolerance under mild reaction conditions without a metal catalyst participation. A series of valuable indolo[2,1-α] isoquinoline derivatives bearing various functional groups were synthesized using this method in good to excellent yields. Based on a series of control experiments, a radical pathway was proposed to explain the experiment.

Copper(II)-catalysed direct C3-H esterification of indoles assisted by an N,N-bidentate auxiliary moiety.

The regioselective direct C3-esterification of indoles with OXA is developed in an efficient reaction with carboxylic acids using the catalyst CuBr2 and oxidants Ag2CO3 and K2S2O8. The simple experimental procedure is proved to be broadly applicable to a range of substrates, including aromatic and aliphatic acids, and the corresponding products were obtained in good yields up to 87%. At the same time, it provides a valuable approach to produce C3-benzyl derivatives of indoles through reaction with benzyl carboxylic acid under the same reaction conditions.

An apple MYB transcription factor regulates cold tolerance and anthocyanin accumulation and undergoes MIEL1-mediated degradation.

MYB transcription factors (TFs) have been demonstrated to play diverse roles in plant growth and development through interaction with basic helix-loop-helix (bHLH) TFs. MdbHLH33, an apple bHLH TF, has been identified as a positive regulator in cold tolerance and anthocyanin accumulation by activating the expressions of MdCBF2 and MdDFR. In the present study, a MYB TF MdMYB308L was found to also positively regulate cold tolerance and anthocyanin accumulation in apple. We found that MdMYB308L interacted with MdbHLH33 and enhanced its binding to the promoters of MdCBF2 and MdDFR. In addition, an apple RING E3 ubiquitin ligase MYB30-INTERACTING E3 LIGASE 1 (MdMIEL1) was identified to be an MdMYB308L-interacting protein and promoted the ubiquitination degradation of MdMYB308L, thus negatively regulated cold tolerance and anthocyanin accumulation in apple. These results suggest that MdMYB308L acts as a positive regulator in cold tolerance and anthocyanin accumulation in apple by interacting with MdbHLH33 and undergoes MdMIEL1-mediated protein degradation. The dynamic change in MYB-bHLH protein complex seems to play a key role in the regulation of plant growth and development.

Methylome and transcriptome analyses of apple fruit somatic mutations reveal the difference of red phenotype.

BACKGROUND: Fruit peel colour is an important agronomic trait for fruit quality. Cytosine methylation plays an important role in gene regulation. Although the DNA methylation level of a single gene is important to affect the phenotype of mutation, there are large unknown of difference of the DNA methylation in plant and its mutants. RESULTS: Using bisulfite sequencing (BS-Seq) and RNA-sequencing (RNA-Seq), we analysed three deep-red-skinned apple (Malus × domestica) mutants (Yanfu 3, YF3; Yanfu 8, YF8; Shannonghong, SNH) and their lighter-skinned parents (Nagafu 2, NF2; Yanfu 3, YF3; Ralls, RL) to explore the different changes in methylation patterns associated with anthocyanin concentrations. We identified 13,405, 13,384, and 10,925 differentially methylated regions (DMRs) and 1987, 956, and 1180 differentially expressed genes (DEGs) in the NF2/YF3, YF3/YF8, and RL/SNH comparisons, respectively. And we found two DMR-associated DEGs involved in the anthocyanin pathway: ANS (MD06G1071600) and F3H (MD05G1074200). These genes exhibited upregulated expression in apple mutants, and differences were observed in the methylation patterns of their promoters. These results suggested that both the regulatory and structural genes may be modified by DNA methylation in the anthocyanin pathway. However, the methylation of structural genes was not the primary reason for expression-level changes. The expression of structural genes may be synergistically regulated by transcription factors and methylation changes. Additionally, the expression of the transcription factor gene MYB114 (MD17G1261100) was upregulated in the deep-red-skinned apple. CONCLUSION: Through the analysis of global methylation and transcription, we did not find the correlation between gene expression and the DNA methylation. However, we observed that the upregulated expression of ANS (MD06G1071600) and F3H (MD05G1074200) in apple mutants results in increased anthocyanin contents. Moreover, MYB114 (MD17G1261100) is likely another regulatory gene involved in apple coloration. Our data provided a new understanding about the differences in formation of apple colour mutants.

Weak red light plays an important role in awakening the photosynthetic machinery following desiccation in the subaerial cyanobacterium Nostoc flagelliforme.

The subaerial cyanobacterium Nostoc flagelliforme can survive for years in the desiccated state and light exposure may stimulate photosynthetic recovery during rehydration. However, the influence of light quality on photosynthetic recovery and the underlying mechanism remain unresolved. Exposure of field collected N. flagelliforme to light intensity ≥2 µmol photons m-2 s-1 showed that the speed of photosystem II (PSII) recovery was in the following order: red > green > blue ≈ violet light. Decreasing the light intensity showed that weak red light stimulated PSII recovery during rehydration. The chlorophyll fluorescence transient and oxygen evolution activity indicated that the oxygen evolution complex (OEC) was the activated site triggered by weak red light. The damaged D1 protein accumulated in the thylakoid membrane during dehydration and is degraded and resynthesized during dark rehydration. PsbO interaction with the thylakoid membrane was induced by weak red light. Thus, weak red light plays an important role in triggering OEC photoactivation and the formation of functional PSII during rehydration. In its arid habitats, weak red light could stimulate the awakening of dormant N. flagelliforme after absorbing water from nighttime dew or rain to maximize growth during the early daylight hours of the dry season.

The nickel-catalyzed C3-acylation of 2H-indazoles with aldehydes.

A direct coupling of 2H-indazoles' C3 position and acyl groups has been achieved to produce 3-acyl-2H-indazoles. The Ni(ii)-catalyzed acylation might proceed through a radical pathway for the reaction of 2H-indazoles with either aryl or alkyl aldehydes in the presence of the free radical initiator TBHP and additive PivOH. This method provided a superior approach to fulfil the direct C3-acylation of 2H-indazoles with yields up to 91%. And various substituted 2H-indazoles were well tolerated with this method, enriching the diversity of 2H-indazole derivatives. In comparison with previously reported approaches for the C3-acylation of 2H-indazoles, the developed reaction represents a more convenient and economical method directly using aldehydes as the acylation agents.

Laser-cooling with an intermediate electronic state: Theoretical prediction on bismuth hydride.

The possibility of laser cooling of bismuth hydride (BiH) molecules has been investigated based on high-level ab initio calculations by considering the core-valence and the spin-orbit coupling (SOC) effects. The potential energy curves of the 12 Λ-S states as well as the 25 Ω states that split from them via SOC are obtained by multireference configuration interaction plus the Davidson correction. The properties of b-X transition are investigated. Based on our calculations, we show that the transition between Ω states b0+-X10+ of BiH is a possible candidate for laser cooling, with consideration of the intermediate Ω state X21. An optical cycling scheme is proposed by utilizing four lasers at wavelengths around 471 and 601 nm with 5400 cycles for photon absorption/emission and a sub-microkelvin temperature. Our study should shed some light on searching for possible molecular candidates for laser cooling with the existence of an intermediate electronic state.

UV-B induced biosynthesis of a novel sunscreen compound in solar radiation and desiccation tolerant cyanobacteria.

The small-molecule sunscreen compounds, mycosporine-like amino acids (MAAs), have strong ultraviolet (UV) absorption and can protect cyanobacteria against UV-B damage. However, the molecular mechanism underlying UV-B signaling and MAA chemical diversity remain largely unclear. Here, we identified a five-gene cluster for MAA biosynthesis in the solar radiation and desiccation tolerant cyanobacterium Nostoc flagelliforme. A LuxR family protein OrrA was identified as a positive UV-B responsive regulator binding to the promoter region of this gene cluster. OrrA functions as an activator mediating the UV-B induced MAA biosynthesis. Overexpression of orrA strengthened its UV-B tolerance during desiccation, and enhanced the photosynthetic recovery upon rehydration. Heterologous expression of this gene cluster in Anabaena PCC 7120 produces the same MAA as that in field samples of N. flagelliforme. The MAA structure is assigned as mycosporine-2-(4-deoxygadusolyl-ornithine) with a molecular weight of 756 Da, the structurally unique MAA compound reported to date. This MAA was catalyzed by mysD-mysC2-mysC1 encoding proteins from 4-deoxygadusol, which was synthesized through the catalysis of mysA-mysB products. Thus, we elucidated the transcriptional mechanism for a novel type MAA biosynthesis in solar radiation and desiccation tolerant cyanobacteria, which shed light on the identification of other components for UV-B signaling in cyanobacteria.

Laser cooling of thallium chloride: A theoretical investigation.

The possibility of laser cooling of thallium chloride (TlCl) molecules has been investigated based on high-level ab initio calculations with the consideration of the core-valence and the spin-orbit coupling (SOC) effects. The potential energy curves of the 13 Λ-S states as well as the 24 Ω states split from them via SOC are obtained by multi-reference configuration interaction plus the Davidson correction. We show that the a Π0+3-X1Σ0+ transition of TlCl is a possible candidate for laser cooling, which features highly diagonal Franck-Condon factors and no intermediate interacting electronic states. Based on our calculations, we propose an optical cycling scheme by utilizing four lasers at wavelengths around 320 nm with more than 104 cycles for photon absorption/emission and a sub-microkelvin temperature limit.

Comparison of Safety and Efficacy of Different Models of Target Vessel Regional Chemotherapy for Gastric Cancer with Liver Metastases.

BACKGROUND/AIMS: We previously demonstrated the safety and efficacy of low-dose, short-interval target vessel regional chemotherapy (TVRC(LDSI)) delivered through the hepatic artery with transarterial embolization (TAE) in patients with advanced gastric cancer (AGC). The present study aimed to compare the efficacy of TAE + TVRC(LDSI) with that of standard TAE + TVRC in AGC patients with liver metastases who failed to respond to first- or second-line systemic chemotherapy. METHODS: This study recruited a total of 58 GC patients with liver metastases after failure of first- or second-line systemic chemotherapy. Twenty-eight patients were assigned to the TAE + TVRC(LDSI) group and 30 patients to the TAE + TVRC group. The primary end point was overall survival (OS(TVRC)), which was defined as the time from the initiation of TVRC until the last follow-up or death. RESULTS: OS(TVRC), time to progression (TTP) until appearance of intra- and extrahepatic metastases, and overall TTP and treatment periods in the TAE + TVRC(LDSI) group were all significantly longer than in the TAE + TVRC group (all p < 0.001). CONCLUSION: TAE + TVRC(LDSI) had a higher efficacy and safety, which was reflected by OS rates, progression-free survival rates, longer duration of treatment and milder side effects compared to standard TAE + TVRC.

The response of Golgi protein 73 to transcatheter arterial chemoembolization in patients with hepatocellular carcinoma may relate to the influence of certain chemotherapeutics.

BACKGROUND: Golgi protein 73 (GP73) is a promising biomarker of hepatocellular carcinoma (HCC). It decreases after surgical resection, and resumes upon recurrence, indicating a potential indicator for the effectiveness of the treatment. But changes of GP73 after transcatheter arterial chemoembolization (TACE) have not been reported so far. This study was to investigate the dynamic changes of GP73 in HCC patients after TACE treatment, and the possible underlying mechanisms in the cell cultures. METHODS: Blood samples were collected from 72 HCC patients, before TACE, at day 1 and day 30 after TACE. GP73 levels were measured by Western blotting. The dynamic changes of GP73 were analyzed and compared with image changes and clinical data. The effects of chemotherapeutic agents (5-FU and pirarubicin) on GP73 expression were tested in three HCC cell lines (HepG2, HCCLM3 and MHCC97H). RESULTS: The GP73 level was significantly elevated at day 1 and day 30 after TACE in HCC patients compared with that before the procedure (P<0.05). There was no statistical difference between the two time points after TACE, nor correlation between GP73 levels and clinicopathological features, tumor metastasis, and patient survival. Pirarubicin, not 5-FU, significantly increased GP73 expression in three cell lines. CONCLUSIONS: Unlike surgical resection which decreases the GP73 level, TACE significantly increased GP73 expression in patients with HCC. No correlations were observed among GP73 levels, tumor characteristics and prognosis of patients with HCC.

Expression and clinical significance of STIP1 in papillary thyroid carcinoma.

The aim of this study was to detect stress-induced phosphoprotein 1 (STIP1) expression in papillary thyroid carcinoma (PTC) and to analyze its association with prognosis of PTC patients. Immunohistochemistry was performed to detect the expression of STIP1 in 113 PTC tissues and paired adjacent noncancerous tissues. The χ2 test was used to analyze the relationship between STIP1 expression and clinicopathological characteristics. Survival curves were plotted by the Kaplan-Meier method and compared using the log-rank test. Survival data was evaluated using univariate and multivariate Cox regression analysis. We identified abnormally elevated expression of STIP1 protein in PTC tissues compared to paired adjacent noncancerous tissues. Clinicopathological analysis showed that STIP1 expression was significantly correlated with tumor size (P = 0.017), lymph node metastasis (P = 0.007), and TNM stage (P = 0.026). Patients with higher STIP1 expression had shorter overall survival time, whereas those with lower STIP1 expression had longer survival time. Multivariate analysis suggested that STIP1 expression might be an independent prognostic indicator (P < 0.05) for the survival of patients with PTC. In conclusion, our findings provide evidences that positive expression of STIP1 in PTC may be important in the acquisition of an aggressive phenotype, and it is an independent biomarker for poor prognosis of patients with PTC.

Low-dose, short-interval target vessel regional chemotherapy through the hepatic artery combined with transarterial embolization in gastric cancer patients with liver metastases after failure of first-line or second-line chemotherapy: a preliminary analysis.

The objective of this study is to evaluate the efficacy and safety of combining low-dose, short-interval target vessel regional chemotherapy delivered through the hepatic artery (TVRC) with transarterial embolization (TAE) in advanced gastric cancer (AGC) patients with liver metastases after failure of first-line or second-line chemotherapy. All AGC patients with hepatic metastases had an indwelling arterial catheter placed in the hepatic artery and hepatic metastases were embolized with ultrafluid lipiodol, followed by two to three TVRC treatments in one cycle. After 3 weeks, the efficacy of TVRC treatment was evaluated using computed tomography (CT) or MRI scans before starting the next cycle. Follow-up assessments were performed every 2 months. The patients received a median of 7 (2-33) TVRC treatments together with TAE. All 22 AGC patients received a total of 191 TVRC treatments, which included 80.1% FOLFOX, 11.0% FOLFIRI, and 8.9% DC treatments. The median time-to-progression was 5.97 months; the median survival time was 11.6 months; and the 1-year and 2-year survival rates were 45.5 and 9.1%, respectively. The median overall survival from the diagnosis of liver metastasis (mOS) was 19.3 months. The most common side effects were grade I-II of abdominal pain, nausea, and vomiting. Combining TAE and TVRC administration through the hepatic artery for AGC patients with liver metastases resulted in decreased overall dose of chemotherapy, alleviation of side effects, and increased QOL of patient. This approach can be used as salvage therapy for AGC patients with predominant liver metastases after failure of intravenous chemotherapy.