Function and organization of photosystem I in a cyanobacterial mutant strain that lacks PsaF and PsaJ subunits

Photosystem I functions as a light-driven plastocyanin-ferredoxin oxidoreductase in the photosynthetic membranes of cyanobacteria and chloroplasts. A mutant strain of the cyanobacterium Synechocystis sp. PCC 6803 that contains a deletion of the psaF gene and a transcriptionally inactive psaJ gene has assembled photosystem I complexes that lack PsaF, a lumenal protein and PsaJ, a 4-kDa hydrophobic protein. The cells of the mutant and wild type strains have similar rates of photosynthetic electron transfer and P700+ rereduction under linear and cyclic electron transfer conditions. Analysis of flash-induced absorption transients at 700 nm demonstrate that the absence of PsaF in purified mutant photosystem I did not affect the rate of P700 rereduction by cytochrome c553. Therefore, PsaF is not essential for docking of cytochrome c553. We also studied the organization of the proteins of mutant and wild type photosystem I by comparing their accessibility to digestion by thermolysin or to removal by 1 M NaI. The PsaA-PsaB subunits were more easily degraded by thermolysin in the mutant photosystem I. Thermolysin cleavage of PsaB yielded two major fragments that were immunoreactive with an antibody raised against the C terminus of PsaB. The N termini of these PsaB peptides mapped at Ile482 and Ile498 residues, thus identifying a surface-exposed domain of the core of photosystem I. The PsaE subunit could be removed by 1 M NaI and was rapidly digested by thermolysin in the mutant but not in the wild type photosystem I. Therefore, PsaF and PsaJ subunits of photosystem I have dispensable accessory roles in the function and organization of the complex.

Observation of New Ω_{c}^{0} States Decaying to the Ξ_{c}^{+}K^{-} Final State

Two new excited states, Ω_{c}(3185)^{0} and Ω_{c}(3327)^{0}, are observed in the Ξ_{c}^{+}K^{-} invariant-mass spectrum using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1}. Five previously observed excited Ω_{c}^{0} states are confirmed, namely Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3065)^{0}, Ω_{c}(3090)^{0}, and Ω_{c}(3119)^{0}. The masses and widths of these seven states are measured with the highest precision to date.

Evidence of a J/ψK_{S}^{0} Structure in B^{0}→J/ψϕK_{S}^{0} Decays

An amplitude analysis of B^{0}→J/ψϕK_{S}^{0} decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9  fb^{-1}, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. Evidence with a significance of 4.0 standard deviations of a structure in the J/ψK_{S}^{0} system, named T_{ψs1}^{θ}(4000)^{0}, is seen, with its mass and width measured to be 3991_{-10}^{+12} _{-17}^{+9}  MeV/c^{2} and 105_{-25}^{+29} _{-23}^{+17}  MeV, respectively, where the first uncertainty is statistical and the second systematic. The T_{ψs1}^{θ}(4000)^{0} state is likely to be the isospin partner of the T_{ψs1}^{θ}(4000)^{+} state, previously observed in the J/ψK^{+} system of the B^{+}→J/ψϕK^{+} decay. When isospin symmetry for the charged and neutral T_{ψs1}^{θ}(4000) states is assumed, the signal significance increases to 5.4 standard deviations.

[Primary study on heart rate variability of non-linear dynamics in patients with coronary artery disease and diabetes]

This is a comparative study on the non-linear dynamics between 30 healthy controls and three groups of patients with single coronary artery disease(n = 20), multi-coronary disease(n = 8), and diabetic patients with diabetic autonomic neuropathy (DAN)(n = 18), respectively. We selected and adopted six quantity indices of dispersed-dot plot, including the area of plot (SQ), long-axis (LA), short-axis (SA), the angle of long-axis and short-axis (ALS), vector length index (VLI) and vector angle index (VAI), and Kolmogorov entropy and fractal dimension. We found that the non-linear indices in healthy control had obvious day-to-night change, while the change in coronary artery disease patients decreased and disappeared in diabetics. By the findings that both coronary artery disease patients and diabetic patients had the turbulence of vegetal nerve system, we concluded that the vegetal nerve activity might be an important factor in heart non-linear dynamics. And marked differences in the non-linear indices were seen between the normal control, the single-vessel, multi-vessel coronary artery disease patients, and the diabetic patients, thus suggesting that these indices may be used in clinical practice.

Measurement of dijet azimuthal decorrelation in pp collisions at [Formula: see text]

A measurement of the decorrelation of azimuthal angles between the two jets with the largest transverse momenta is presented for seven regions of leading jet transverse momentum up to 2.2[Formula: see text]. The analysis is based on the proton-proton collision data collected with the CMS experiment at a centre-of-mass energy of 8[Formula: see text] corresponding to an integrated luminosity of 19.7[Formula: see text]. The dijet azimuthal decorrelation is caused by the radiation of additional jets and probes the dynamics of multijet production. The results are compared to fixed-order predictions of perturbative quantum chromodynamics (QCD), and to simulations using Monte Carlo event generators that include parton showers, hadronization, and multiparton interactions. Event generators with only two outgoing high transverse momentum partons fail to describe the measurement, even when supplemented with next-to-leading-order QCD corrections and parton showers. Much better agreement is achieved when at least three outgoing partons are complemented through either next-to-leading-order predictions or parton showers. This observation emphasizes the need to improve predictions for multijet production.

Search for W Boson Decays to Three Charged Pions

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3  fb^{-1}, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01×10^{-6} is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction.

[Fetal cardiac intervention and perioperative management of fetus with hypoplastic right heart syndrome]

Objective: To summarize the experience of perioperative management strategy of fetal pulmonary valvuloplasty (FPV) for hypoplastic right heart syndrome (HRHS). Methods: In the retrospective study of perioperative data, 13 fetuses of HRHS were treated with FPV in Qingdao Women and Children's Hospital from July 2018 to June 2019. Results: (1) The evaluation indexes of the right ventricle in 13 fetuses before FPV: the mean ratio of tricuspid/mitral annulus, right/left ventricular length, pulmonary/aortic annulus, and tricuspid inflow time/cardiac cycle were 0.81±0.04, 0.56±0.14, 0.69±0.06, and 0.35±0.03, respectively. (2) All pregnant mothers underwent general anesthesia. The basic fetal heart rate was (156±12) beats per minutes before FPV, and 9 fetuses showed bradycardia during the operation, and recovered to normal after drug resuscitation. On the first day after FPV, two cases had bradycardia and pregnancy was terminated. The fluctuation of systolic blood pressure of pregnant mother was less than 20%, and there was no significant difference between preoperative and intraoperative pulse pressure [(36.0±5.6) vs (35.8±6.9) mmHg (1 mmHg=0.133 kPa); t=8.102, P=0.951]. (3) All cases of HRHS fetus successfully underwent FPV. The average gestational age was (27.3±0.8) weeks. The average operation time was (23.2±1.0) minutes. The ratio of tricuspid to mitral annulus (t=-2.513, P=0.022) and the ratio of right to left ventricular length (t=-3.373, P=0.003) were significantly improved at 6 weeks postoperatively. Ten fetuses were delivered, and there was no death after early intervention. (4) Of 13 pregnant women, 3 cases were nausea and vomiting on the day of FPV operation, the treatment of the symptoms was improved by tropisetron; one case had tolerable abdominal pain and improved without special treatment. Pregnant women had no major complications such as cardiac failure, abortion and death. (5) Chromosome karyotype analysis and microarray analysis of amniotic fluid was retained during the operation. No typical chromosome abnormality or other abnormal genetic diagnosis was found. Conclusions: FPV colud be used as an effective intervention measure to promote the development of right ventricle in HRHS fetuses. The scientific management of multidisciplinary professional technical team in perioperative period is particularly important to ensure the success of FPV and the safety of pregnant women and fetuses.

[Structural equation analysis of the incidence of shoulder WMSDs and individual and work-related factors]

Objective: To investigate the incidence of shoulder work-related musculoskeletal disorders (WMSDs) among occupational population in China, and to explore their intrinsic association with personal and work-related factors. Methods: In April 2024, 73497 valid questionnaires of the Chinese version of the Musculoskeletal Disorders Electronic Questionnaire were retrospectively analyzed from June 2018 to December 2023 in 22 provinces and 29 key industries in China, and the general information, occurrence of WMSDs and related risk factors of key occupational populations in different regions in China were collected. By using Chi-square test and confirmatory factor analysis, the relationship between shoulder fatigue and pain in key occupational groups and individual factors, work type, work posture and work organization was discussed, and the internal relationship was analyzed based on structural equation model. Results: Higher incidence of shoulder fatigue and pain were associated with female, lack of physical exercise, uncomfortable working posture and neck leaning forward (P<0.05). Structural equation model analysis showed that work type, work posture and work organization were strongly correlated (r=0.58, 0.55). Work organization and work type were strongly correlated with shoulder fatigue (r=0.65) and moderately correlated with shoulder fatigue (r=0.21). Shoulder fatigue was moderately associated with shoulder pain (r=0.40). Individual factors, work type, work posture and shoulder fatigue could directly affect shoulder pain (OR=0.07, -0.09, 0.17 and 0.40), and work type and work posture could also indirectly affect shoulder pain through shoulder fatigue (OR=0.08, 0.03). Work organization only indirectly affected shoulder pain through shoulder fatigue (OR=0.26) . Conclusion: The main influencing factor of shoulder pain is shoulder fatigue, followed by work posture and individual factors. Structural equation model can better reflect the complex relationship between work type, work posture and work organization and shoulder WMSDs. Improving work posture and work organization may be an effective way to control the influence of shoulder fatigue on shoulder pain.

[Study on the efficacy and safety profile of tenofovir alafenamide fumarate in the treatment of patients with decompensated hepatitis B cirrhosis]

Objective: To explore the efficacy and safety profile of tenofovir alafenamide fumarate (TAF) in the treatment of patients with decompensated hepatitis B cirrhosis. Methods: A two-way cohort study method was used to enroll patients with decompensated hepatitis B cirrhosis who visited four medical centers, including Xinjiang Uygur Autonomous Region Hospital of Traditional Chinese Medicine, from April 2021 to April 2024 and were treated with TAF and followed up for 48 weeks. The primary efficacy indicator was hepatitis B virus (HBV) DNA seronegative conversion rate at 48-weeks, and the secondary efficacy indicator was alanine aminotransferase (ALT) return to normal rate at 48-weeks. Relevant safety indicators, adverse drug reactions (ADRs), and clinical adverse outcomes were collected. Results: A total of 74 cases were included. Of these, 52 were males with an average age of (53.14 ± 9.15) years. Twenty-five and thirty-three cases completed 24 and 48 weeks of follow-up, respectively. The HBV DNA negative conversion rate was 96.97% (32/33), which was higher than the baseline of 58.1% (43/74) following 48 weeks of TAF treatment. The ALT return to normal rate was 72.73% (24/33), which was higher than the baseline of 47.30% (35/74); however, the renal function and blood lipid levels did not change significantly compared with the baseline level after completing 48 weeks of treatment (P>0.05). During the follow-up period, one case developed hepatocellular carcinoma, and no other adverse clinical outcomes, such as liver transplantation or death, were reported. Conclusion: TAF has a good efficacy and safety profile in the treatment of patients with decompensated hepatitis B cirrhosis.

[Correlation between uterine volume and intrauterine adhesion: a propensity score matching analysis]

Objective: To investigate the correlation between uterine volume and intrauterine adhesion (IUA). Methods: From June 2018 to November 2019, totally 7 007 patients who underwent hysteroscopy in outpatient operating rooms of Gynecological Minimally Invasive Center, Beijing Obstetrics and Gynecology Hospital were retrospectively analyzed. Patients of reproductive age with IUA without uterine fibroids and adenomyosis were selected as IUA group, and patients of reproductive age without uterine fibroids and adenomyosis without IUA during the same period were selected as the control group. The propensity score matching (PSM) method was used to perform 1∶1 matching for the two groups of patients, matching variables included age, height, weight, body mass index (BMI), gravidity, parity, and number of abortion curettage. Whether there was any difference in uterine volume between the two groups of patients was compared, and whether uterine volume was an influencing factor of IUA was explored. The patients in IUA group were also categorized into mild, moderate and severe to explore whether uterine volume influenced the severity of IUA. Results: (1) After inclusion and exclusion criteria, 351 patients were included in IUA group and 2 986 patients in the control group. With PSM, 327 patients in IUA group and 327 patients in the control group were finally enrolled in this study. There were no statistically significant differences in age, height, weight, BMI, gravidity, parity, and number of abortion curettage between the two groups of patients after matching (all P>0.05). (2) After PSM, there was a significant difference between the uterine volume of IUA group (median: 44.23 cm3) and the uterine volume of the control group (median: 57.20 cm3; P<0.001). (3) Reduced uterine volume (OR=0.961, 95%CI: 0.952-0.970) was an independent risk factor for IUA (P<0.001). (4) Uterine volume had a significant effect on the severity of IUA (P<0.001), the larger the uterine volume (B=-0.030, 95%CI: -0.044 to -0.017), the less severe the IUA. Conclusions: Reduced uterine volume is an independent risk factor for IUA, and uterine volume has a significant effect on the severity of IUA. In patients with small uterine volume size, primary and secondary prevention of IUA should be emphasized.

[Synthesis of S(+)-2-(4-isobutylphenyl) propionic acid by asymmetric hydrolysis of microbial enzyme. II. Reaction conditions and product extraction]

Trichosporon cutaneum 158 exhibited higher sterospecificity to hydrolyze substrate ibuprofen ester. Among the five chosen substrate, asymmetric hydrolysis of methyl ester or isopropyl ester formed S(+)-ibuprofen of 97% ee. While ethyl ester not only gave ee 93% but also showed the highest hydrolytic activity. The optimum pH range for asymmetric hydrolysis was 6.5-7.0. Ability of resolusion was stabler in the range of temperature 28-37 degrees C. This yeast produced intracellular enzyme. Hydrolysis can be carried out by powered cells treated by iced-acetone to improve the specificity of resolution. The product S(+)-ibuprofen can be got with acid-base reaction and organic solvent extraction, unreacted esters can be recovered simultaneously.

Studies on RNA ligase activity in the brain and liver cells of mouse

RNA ligase in eukaryotic mammalian cells was studied by using mouse brain and liver cell extracts as enzyme sources and Oligo A as substrates. RNA ligase activity was determined by measuring the formation of alkaline phosphate-resistant product from 5'-32P-terminated Oligoribonucleotides. Under appropriate conditions, the activity of this enzyme in brain and liver cells may vary between 16-49 mU/ml. The joining way between donor and acceptor is 5'-P----3'-OH. Further studies were carried out by using synthetic UpCpU and 32pNp as substrates and crude enzyme preparations from extracts of cell nuclei of brain and liver as enzyme sources. RNA ligase activity was examined by homochromatography and autoradiography. A clear joining product was demonstrated and then isolated from the reaction mixture by DEAE-Sephadex A25 column chromatography. The eluted fractions were identified by DEAE-cellulose thin layer chromatography. The joining product was hydrolyzed either with KOH or with alkaline phosphatase, the autoradiographic spot of the product disappeared. In this case the joining way between donor and acceptor is 3'-P----5'-OH instead of 5'P----3'-OH. All this indicated that in extracts of mouse brain and liver cells most probably exists some other kind of RNA ligase, which differs from the T4 RNA ligase in the joining way.

[HLA-DR typing by standard serology and PCR-amplification with sequence-specific primers: a comparative study]

OBJECTIVE

DNA typing for HLA-DR by polymerase chain reaction with sequence-specific primers (PCR-SSP) compared with standard serology to evaluate the reliability and clinical practicability.

METHODS

Double-blind typing for HLA-DR alleles was carried out using DNA typing by PCR-SSP and standard serology by microlymphocytotoxicity technique in 61 donors and 101 recipients of cadaveric transplantation. Matching time, sensitivity, specificity and clinical practicability were compared according to typing results by both methods.

RESULTS

All 162 samples were able to be typed by PCR-SSP. A total of 308 alleles were detected (16 DR "blank"). The results of matching were confirmed by analysis with restriction endonucleases and Southern hybridization. The specificity and reproducibility were 100%. HLA-DR typing was performed in 5 hours by PCR-SSP or 20 hours by serology. The discrepancy rate between PCR-SSP and serological HLA-DR typing was 30.2% (35.6% for kidney recipients, 21.3% for donors). The discrepancies consisted of 8 loci being doubtful, 29 antigens being incorrectly interpreted by serology and 20 of serological "blanks" turning out to be definable alleles by the DNA method.

CONCLUSIONS

Genotyping for HLA-DR by PCR-SSP offers the advantages of better reagent and sample availability, more rapid and greater accuracy, all of which would warrant that this approach was suitable for clinical practice in organ transplantation.