A pyrenoid-localized protein SAGA1 is necessary for Ca2+-binding protein CAS-dependent expression of nuclear genes encoding inorganic carbon transporters in Chlamydomonas reinhardtii.

Microalgae induce a CO2-concentrating mechanism (CCM) to maintain photosynthetic affinity for dissolved inorganic carbon (Ci) under CO2-limiting conditions. In the model alga Chlamydomonas reinhardtii, the pyrenoid-localized Ca2+-binding protein CAS is required to express genes encoding the Ci-transporters, high-light activated 3 (HLA3), and low-CO2-inducible protein A (LCIA). To identify new factors related to the regulation or components of the CCM, we isolated CO2-requiring mutants KO-60 and KO-62. These mutants had insertions of a hygromycin-resistant cartridge in the StArch Granules Abnormal 1 (SAGA1) gene, which is necessary to maintain the number of pyrenoids and the structure of pyrenoid tubules in the chloroplast. In both KO-60 and the previously identified saga1 mutant, expression levels of 532 genes were significantly reduced. Among them, 10 CAS-dependent genes, including HLA3 and LCIA, were not expressed in the saga1 mutants. While CAS was expressed normally at the protein levels, the localization of CAS was dispersed through the chloroplast rather than in the pyrenoid, even under CO2-limiting conditions. These results suggest that SAGA1 is necessary not only for maintenance of the pyrenoid structure but also for regulation of the nuclear genes encoding Ci-transporters through CAS-dependent retrograde signaling under CO2-limiting stress.

Unambiguous Imaging of Static Scenes and Moving Targets with the First Chinese Dual-Channel Spaceborne SAR Sensor.

Multichannel synthetic aperture radar (SAR) is a breakthrough given the inherent limitation between high-resolution and wide-swath (HRWS) faced with conventional SAR. This paper aims to obtain unambiguous imaging of static scenes and moving targets with the first Chinese dual-channel spaceborne SAR sensor. We propose an integrated imaging scheme with the dual-channel echoes. In the imaging scheme, the subspace-based error estimation algorithm is first applied to the spaceborne multichannel SAR system, followed by the reconstruction algorithm prior to imaging. The motion-adapted reconstruction algorithm for moving target imaging is initially achieved with the spaceborne multichannel SAR system. The results exhibit an effective suppression of azimuth ambiguities and false targets with the proposed process. This paper verifies the accuracy of the subspace-based channel error estimator and the feasibility of the motion-adapted reconstruction algorithm. The proposed imaging process has prospects for future HRWS SAR systems with more channels.

Effect of intensive care unit diary on quality of life of intensive care unit survivors and their relatives: A systematic review and meta-analysis.

AIM: To evaluate the current literature on the effect of ICU diaries on the quality of life of ICU survivors and their relatives. DESIGN: Systematic review and meta-analysis. METHODS: We searched the online databases Web of Science, PubMed, Embase, The Cochrane Library, CNKI and WanFang from inception to April 2021. Cochrane Risk of Bias Assessment Tool and Newcastle-Ottawa Scale (NOS) were used to assess the methodological quality. RESULTS: Seven studies were identified. ICU diaries improved the QoL of ICU survivors (SMD 0.79, 95% CI 0.24-1.34), and a small study described no benefit of diaries in improving the QoL of relatives. CONCLUSION: This meta-analysis revealed the use of ICU diaries to improve the QoL in survivors, but the ICU diaries do not have a beneficial effect on the QoL in relatives. The evidence summarized in our study is limited and biased, and more research should be carried out to verify it.

Essential oil of Artemisia vestita exhibits potent in vitro and in vivo antibacterial activity: Investigation of the effect of oil on biofilm formation, leakage of potassium ions and survival curve measurement.

The aim of the present study was to investigate the chemical composition of the essential oil of Artemisia vestita and to determine the antibacterial activity of the essential oil and its two major components, grandisol and 1,8­cineole, against certain respiratory infection­causing bacterial strains, in vitro and in vivo. The chemical composition of the essential oil was analyzed using gas chromatography­mass spectrometry. A micro­well dilution method was used to determine the minimum inhibition concentration (MIC) values of the essential oil and its major constituents. A model of Streptococcus pyogenes infection in mice was used to determine its in vivo activities. Lung and blood samples were obtained to assess bacterial cell counts. Toxicity evaluation of the essential oil and its components was completed by performing biochemical analysis of the serum, particularly monitoring aspartate transaminase, alanine transaminase, urea and creatinine. The essential oil exhibited potent antibacterial activity, whereas the two major constituents were less potent. The essential oil exhibited MIC values between 20 and 80 µg/ml, while the values of the two constituents were between 130 and 200 µg/ml. Scanning electron microscopy results demonstrated that the essential oil inhibited biofilm formation and altered its architecture. Survival curves indicated that the essential oil led to a reduction in the viability of different bacteria. The essential oil also induced significant leakage of potassium ions from S. pyogenes. The essential oil (100 µg/mouse) and grandisol (135 µg/mouse) significantly reduced the number of viable bacterial cells in the lungs (P<0.01). However, intake of 100 µg/mouse of essential oil or grandisol 135 µg/mouse once or twice each day for 9 days did not produce any toxic effects in the mice. In conclusion, the in vitro and in vivo results suggested that the essential oil of A. vestita and one of its major constituents, grandisol, can significantly inhibit the growth of different bacterial strains.

Antibacterial activity and mode of action of the Artemisia capillaris essential oil and its constituents against respiratory tract infection-causing pathogens.

Inhalation therapy using essential oils has been used to treat acute and chronic sinusitis and bronchitis. The aim of the present study was to determine the chemical composition of the essential oil of Artemisia capillaris, and evaluate the antibacterial effects of the essential oil and its main components, against common clinically relevant respiratory bacterial pathogens. Gas chromatography and gas chromatography­mass spectrometry revealed the presence of 25 chemical constituents, the main constituents being: α­pinene, ß­pinene, limonene, 1,8­cineole, piperitone, ß­caryophyllene and capillin. The antibacterial activities of the essential oil, and its major constituents, were evaluated against Streptococcus pyogenes, methicillin­resistant Staphylococcus aureus (MRSA), MRSA (clinical strain), methicillin­gentamicin resistant Staphylococcus aureus (MGRSA), Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae and Escherichia coli. The essential oil and its constituents exhibited a broad spectrum and variable degree of antibacterial activity against the various strains. The essential oil was observed to be much more potent, as compared with any of its major chemical constituents, exhibiting low minimum inhibitory and bacteriocidal concentration values against all of the bacterial strains. The essential oil was most active against S. pyogenes, MRSA (clinical strain), S. pneumoniae, K. pneumoniae, H. influenzae and E. coli. Piperitone and capillin were the most potent growth inhibitors, among the major chemical constituents. Furthermore, the essential oil of A. capillaris induced significant and dose­dependent morphological changes in the S. aureus bacterial strain, killing >90% of the bacteria when administered at a higher dose; as determined by scanning electron microscopy. In addition, the essential oil induced a significant leakage of potassium and phosphate ions from the S. aureus bacterial cultures. These results indicate that the antibacterial action of A. capillaris essential oil may be mediated through the leakage of these two important ions. In conclusion, A. capillaris essential oil exhibits potent antibacterial activity by inducing morphological changes and leakage of ions in S. aureus bacterial cultures.

Umbelliferone exhibits anticancer activity via the induction of apoptosis and cell cycle arrest in HepG2 hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a highly malignant tumor, associated with poor patient prognoses, and high rates of morbidity and mortality. To date, the therapeutic strategies available for the treatment of HCC remain limited. The present study aimed to elucidate the anticancer activity of umbelliferone, a naturally occurring coumarin derivative isolated from Ferula communis, against the HepG2 HCC cell line. A 3­(4,5­dimthylthaizol­2­yl)­2,5, diphenyltetrazolium bromide assay was used to evaluate cell viability following umbelliferone treatment, and the effects of umbelliferone on cell cycle progression and apoptosis were evaluated using flow cytometry. The presence of morphological features characteristic of apoptosis, including cell shrinkage, membrane blebbing, nuclear condensation and apoptotic body formation, were evaluated in HepG2 cells following umbelliferone treatment. Cell cycle analysis conducted via propidium iodide (PI) staining indicated that umbelliferone treatment induced cell cycle arrest at S phase in HepG2 cells. Analysis with Annexin V and PI staining revealed that umbelliferone induced apoptotic events in HepG2 cells in a concentration­dependant manner (0­50 µM). Umbelliferone also induced dose­dependant DNA fragmentation. In conclusion, umbelliferone was found to exhibit significant anticancer effects via the induction of apoptosis, cell cycle arrest and DNA fragmentation in HepG2 cancer cells.