Sll1466, a glycosyl transferase homolog involved in global cellular regulation and high-light tolerance of Synechocystis PCC6803.

In Synechocystis sp. PCC 6803, the loop domain (aa 1-70) of the phycobilisome core-membrane linker, L(CM), was found to interact with the glycosyl transferase homolog, Sll1466. Growth of a Sll1466 knock-out mutant was slightly faster in low light, but strongly inhibited in high light; the phenotype is discussed in relation to the regulation of light energy transfer to photosystem II. At the molecular level, the mutant shows the following changes compared to the wild type: (1) a smaller size and higher mobility of phycobilisomes on the thylakoid membrane, and (2) a changed lipid composition of the thylakoid membrane, especially decreased amounts of digalactosyl diacylglycerol. These results indicate a profound regulatory role for Sll1466 in regulating photosynthetic energy transfer.

Clinical efficacy of treatment for primary tracheal tumors by flexible bronchoscopy: Airway stenosis recanalization and quality of life.

The aim of the present study was to evaluate the effectiveness of interventional treatment of primary tracheal tumors through flexible bronchoscopy. The clinical data of 38 patients with primary tracheal tumours who underwent flexible bronchoscopy intervention therapy between January 2011 and January 2017 were retrospectively analyzed. The average time interval from onset of symptoms to the appearance of actual clinical manifestations in the 38 patients ranged from 0 to 60 months, with an average of 8.1±11.6 months and a median of 4.2 months. The rate of misdiagnosis at the first visit was 36.8% (14/38). After interventional treatment, the overall efficiency (complete + partial response) of airway stenosis recanalization in the 38 patients was 89.5%. In 3 patients with benign tumors, the anhelation score was reduced following treatment (1.00±0.77 vs. 3.13±1.21 at the pre-treatment stage; P<0.001). The overall survival rates of the 35 patients at 1, 3 and 5 years were 69.3, 48.7 and 20.3%, respectively. Therefore, flexible bronchoscopic intervention may effectively smoothen the airways of patients and relieve the symptoms of anhelation. Combining radiotherapy and chemotherapy may improve patient prognosis and safety.

Chinese physicians' perceptions of fecal microbiota transplantation.

AIM: To explore Chinese physicians' perceptions towards fecal microbiota transplantation (FMT) and to provide information and an assessment of FMT development in China. METHODS: A self-administered questionnaire was developed according to the FMT practice guidelines and was distributed to physicians in hospitals via Internet Research Electronic Data Capture (REDcap) software and electronic mails to assess their attitudes toward and knowledge of FMT. The questionnaire included a brief introduction of FMT that was followed by 20 questions. The participants were required to respond voluntarily, under the condition of anonymity and without compensation. Except for the fill-in-the-blank questions, all of the other questions were required in the REDcap data collection systems, and the emailed questionnaires were completed based on eligibility. RESULTS: Up to December 9, 2014, 844 eligible questionnaires were received out of the 980 distributed questionnaires, with a response rate of 86.1%. Among the participants, 87.3% were from tertiary hospitals, and there were 647 (76.7%) gastroenterologists and 197 (23.3%) physicians in other departments (non-gastroenterologists). Gastroenterologists' awareness of FMT prior to the survey was much higher than non-gastroenterologists' (54.3 vs 16.5%, P < 0.001); however, acceptance of FMT was not statistically different (92.4 vs 87.1%, P = 0.1603). Major concerns of FMT included the following: acceptability to patients (79.2%), absence of guidelines (56.9%), and administration and ethics (46.5%). On the basis of understanding, the FMT indications preferred by physicians were recurrent Clostridium difficile infection (86.7%), inflammatory bowel disease combined with Clostridium difficile infection (78.6%), refractory ulcerative colitis (70.9%), ulcerative colitis (65.4%), Crohn's disease (59.4%), chronic constipation (43.7%), irritable bowel syndrome (39.1%), obesity (28.1%) and type 2 diabetes (23.9%). For donor selection, the majority of physicians preferred individuals with a similar gut flora environment to the recipients. 76.6% of physicians chose lower gastrointestinal tract as the administration approach. 69.2% of physicians considered FMT a safe treatment. CONCLUSION: Chinese physicians have awareness and a high acceptance of FMT, especially gastroenterologists, which provides the grounds and conditions for the development of this novel treatment in China. Physicians' greatest concerns were patient acceptability and absence of guidelines.

Spectroscopic investigation on the energy transfer process in photosynthetic apparatus of cyanobacteria.

In this work, we employ cyanobacteria, Spirulina platensis, and separate their photosynthetic apparatus, phycobilisome (PBS), thylakoid membrane and phycobilisome-thylakoid membrane complex. The steady state absorption spectra, fluorescence spectra and corresponding deconvoluted spectra and picosecond time-resolved spectra are used to investigate the energy transfer process in phycobilisome-thylakoid membrane complex. The results on steady state spectra show chlorophylls of the photosystem II are able to transfer excitation energy to phycobilisome with Chla molecules selectively excited. The decomposition of the steady state spectra further suggest the uphill energy transfer originate from chlorophylls of photosystem II to cores of phycobilisome, while rods and cores of phycobilisome cannot receive energy from the chlorophylls of photosystem I. The time constant for the back energy transfer process is 18 ps.

Photophysical diversity of two novel cyanobacteriochromes with phycocyanobilin chromophores: photochemistry and dark reversion kinetics.

Cyanobacteriochromes are phytochrome homologues in cyanobacteria that act as sensory photoreceptors. We compare two cyanobacteriochromes, RGS (coded by slr1393) from Synechocystis sp. PCC 6803 and AphC (coded by all2699) from Nostoc sp. PCC 7120. Both contain three GAF (cGMP phosphodiesterase, adenylyl cyclase and FhlA protein) domains (GAF1, GAF2 and GAF3). The respective full-length, truncated and cysteine point-mutated genes were expressed in Escherichia coli together with genes for chromophore biosynthesis. The resulting chromoproteins were analyzed by UV-visible absorption, fluorescence and circular dichroism spectroscopy as well as by mass spectrometry. RGS shows a red-green photochromism (λ(max) = 650 and 535 nm) that is assigned to the reversible 15Z/E isomerization of a single phycocyanobilin-chromophore (PCB) binding to Cys528 of GAF3. Of the three GAF domains, only GAF3 binds a chromophore and the binding is autocatalytic. RGS autophosphorylates in vitro; this reaction is photoregulated: the 535 nm state containing E-PCB was more active than the 650 nm state containing Z-PCB. AphC from Nostoc could be chromophorylated at two GAF domains, namely GAF1 and GAF3. PCB-GAF1 is photochromic, with the proposed 15E state (λ(max) = 685 nm) reverting slowly thermally to the thermostable 15Z state (λ(max) = 635 nm). PCB-GAF3 showed a novel red-orange photochromism; the unstable state (putative 15E, λ(max) = 595 nm) reverts very rapidly (τ ~ 20 s) back to the thermostable Z state (λ(max) = 645 nm). The photochemistry of doubly chromophorylated AphC is accordingly complex, as is the autophosphorylation: E-GAF1/E-GAF3 shows the highest rate of autophosphorylation activity, while E-GAF1/Z-GAF3 has intermediate activity, and Z-GAF1/Z-GAF3 is the least active state.

GSTP1, ERCC1 and ERCC2 polymorphisms, expression and clinical outcome of oxaliplatin-based adjuvant chemotherapy in colorectal cancer in Chinese population.

AIM: Platinum agents have shown to be effective in the treatment of colorectal cancer. We assessed whether single nucleotide polymorphisms (SNPs) in GSTP1, ERCC1 Asn118Asn and ERCC2 Lys751Gln might predict the overall survival in patients receiving oxaliplatin-based chemotherapy in a Chinese population. METHODS: SNPs of GSTP1, ERCC1 Asn118Asn and ERCC2 Lys751Gln in 335 colorectal cancer patients were assessed using TaqMan nuclease assays. RESULTS: At the time of final analysis on Nov. 2011, the median follow-up period was 37.7 months (range from 1 to 60 months). A total of 229 patients died during follow-up. Our study showed GSTP1 Val/Val (HR=0.44, 95% CI=0.18-0.98), ERCC1 C/C (HR=0.20, 95% CI=0.10-0.79) and ERCC2 G/G (HR=0.48, 95% CI=0.19-0.97) to be significantly associated with better survival of colorectal cancer. GSTP1 Val/Val, ERCC1 C/C and ERCC2 G/G were also related to longer survival among patients with colon cancer, with HRs (95% CIs) of 0.41 (0.16-0.91), 0.16 (0.09-0.74) and 0.34 (0.16-0.91), respectively. CONCLUSION: GSTP1, GSTP1, ERCC1 Asn118Asn and ERCC2 Lys751Gln genotyping might facilitate tailored oxaliplatin-based chemotherapy for colorectal cancer patients.

High-light induced singlet oxygen formation in cytochrome b(6)f complex from Bryopsis corticulans as detected by EPR spectroscopy.

Electron paramagnetic resonance (EPR) spectroscopy was used to detect the light-induced formation of singlet oxygen ((1)O(2)*) in the intact and the Rieske-depleted cytochrome b(6)f complexes (Cyt b(6)f) from Bryopsis corticulans, as well as in the isolated Rieske Fe-S protein. It is shown that, under white-light illumination and aerobic conditions, chlorophyll a (Chl a) bound in the intact Cyt b(6)f can be bleached by light-induced (1)O(2)*, and that the (1)O(2)* production can be promoted by D(2)O or scavenged by extraneous antioxidants such as l-histidine, ascorbate, beta-carotene and glutathione. Under similar experimental conditions, (1)O(2)* was also detected in the Rieske-depleted Cyt b(6)f complex, but not in the isolated Rieske Fe-S protein. The results prove that Chl a cofactor, rather than Rieske Fe-S protein, is the specific site of (1)O(2)* formation, a conclusion which draws further support from the generation of (1)O(2)* with selective excitation of Chl a using monocolor red light.