Regulation of adenosine 5′-phosphosulfate sulfotransferase activity by H2S and cyst(e)ine in primary leaves of Phaseolus vulgaris L.

During chloroplast development in the primary leaves of Phaseolus vulgaris, the extractable activity of adenosine 5-phosphosulfate sulfotransferase increased ten-fold. When chloroplast development took place in air enriched with 3.5 l H₂S·l^-1 there was a decrease in adenosine 5-phosphosulfate sulfotransferase activity. Cyst(e)ine in concentrations up to 1 mM (in the external medium) did not affect the increase in adenosine 5-phosphosulfate sulfotransferase activity in intact plants. In plants with excised roots, 0.75 mM cyst(e)ine inhibited this increase. In green primary leaves, H₂S or cyst(e)ine treatment resulted in a decrease of extractable adenosine 5-phosphosulfate sulfotransferase activity. In intact plants, this effect of cyst(e)ine was observed at a concentration of 1 mM, and in plants with excised roots, 0.25 mM had a comparable effect.In developing plants, the extractable activities of O-acetyl-L-serine sulfhydrylase (EC 4.2.99.9) and ribulosebisphosphate carboxylase (EC 4.1.1.39.) were not affected by H₂S or cyst(e)ine.Abbreviations APS adenosine 5-phosphosulfate - APSSTase adenosine 5phosphosulfate sulfotransferase - BSA bovine serum albumin - DTE dithioerythritol - EDTA ethylenediaminetetra-acetic acid - OASSase O-acetyl-L-serine sulfhydrylase - PAPS adenosine 3-phosphate 5-phosphosulfate - POPOP 1,4 Di 2-(5-phenyloxazolyl)-benzene - PPO 2,5-diphenyloxazol - RubP ribulose-bisphosphate - RubPCase ribulosebiphosphate carboxylase This is no. 8 in the series Regulation of Sulfate Assimilation in Plants. The term cysteine is used when it is clear that cystine is not involved; cyst(e)ine is used for an undefined mixture of cysteine and cystine. The concentrations are expressed in all cases relative to cysteine     

Anaerobic degradation of sorbic acid by sulfate-reducing and fermenting bacteria: pentanone-2 and isopentanone-2 as byproducts

Strictly anaerobic bacteria were enriched and isolated from freshwater sediment sources in the presence and absence of sulfate with sorbic acid as sole source of carbon and energy. Strain WoSo1, a Gram-negative vibrioid sulfate-reducing bacterium which was assigned to the species Desulfoarculus (formerly Desulfovibrio) baarsii oxidized sorbic acid completely to CO₂ with concomitant stoichiometric reduction of sulfate to sulfide. This strain also oxidized a wide variety of fatty acids and other organic compounds. A Gram-negative rod-shaped fermenting bacterium, strain AmSo1, fermented sorbic acid stoichiometrically to about equal amounts of acetate and butyrate. At concentrations higher than 10 mM, sorbic acid fermentation led to the production of pentanone-2 and isopentanone-2 (3-methyl-2-butanone) as byproducts. Strain AmSo1 fermented also crotonate and 3-hydroxybutyrate to acetate and butyrate, and hexoses to acetate, ethanol, hydrogen, and formate. The guanine-plus-cytosine content of the DNA was 41.8±1.0 mol%. Sorbic acid at concentrations higher than 5 mM inhibited growth of this strain while strain WoSo1 tolerated sorbic acid up to 10 mM concentration.     

The effect of two proteinase inhibitors, E-64 and the Bowman-Birk inhibitor, on the developmental time and mortality of Acanthoscelides obtectus

An artificial bean seed system was used to evaluate the effects of a cysteine proteinase inhibitor (E-64) and a serine proteinase inhibitor (Bowman-Birk inhibitor) on the developmental time and mortality of the common bean weevil, Acanthoscelides obtectus (Say). These inhibitors were incorporated into artificial bean seeds on which the insect fed. To better understand the mode of action of these inhibitors, free amino acids were also added to the seeds, alone and in combination with the inhibitors. E-64 was found to be highly effective in delaying development and increasing mortality of the insect. Both effects were directly related to the concentration of E-64. Bowman-Birk inhibitor had little effect on these parameters. Assays of gut proteolytic activity of insects reared on artificial seeds with various levels of E-64 demonstrated a direct relationship between E-64 concentration in the diet and reduction of gut proteolytic activity. Free amino acid supplementation to the diet did not prevent inhibition of gut proteolytic activity by E-64, but did reverse its effects on developmental time and mortality, strengthening the hypothesis that E-64 operates by inhibition of essential digestive proteinase activity.

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Résumé Des grains artificiels de haricot ont été utilisés pour évaluer les effets sur la durée de développement et la mortalité d' Acanthoscelides obtectus. Say d'inhibiteurs de la protéinase de la cystéine (E-64) et de la protéinase de la sérine (l'inhibiteur de Bowman-Birk). Ces inhibiteurs avaient été incorporés dans les grains artificiels. Pour mieux comprendre leur voie d'action, des acides aminés libres étaient ajoutés à ces graines, seuls ou combinés aux inhibiteurs. E-64 a très efficacement retardé le développement et accru la mortalité; ces 2 effets étaient liés à sa concentration. L'inhibiteur de Bowman-Birk a eu peu d'effets sur ces paramètres. Des expériences sur l'activité protéolytique du tube digestif d'insectes élevés sur des graines artificielles avec différentes concentrations de E-64 ont montré une relation directe entre la concentration en E-64 et la réduction de l'activité protéolytique. L'addition d'acides aminés libres dans l'aliment n'a pas empêché l'inhibition de l'activité protéolytique par E-64, mais a inversé ses effets sur la durée de développement et la mortalité, renforçant l'hypothèse que E-64 agit en inhibant l'activité protéinase digestive essentielle.

     

Proteolytic fragmentation of myosin: location of SH-1 and SH-2 thiols.

The heavy chain fragmentation pattern of native myosin when digested by proteolytic enzymes is influenced by such conditions as the nature of the proteolytic agent, ionic strength and presence or absence of divalent cations. HMM and S-1 produced by digestion of 14CNEM-labelled myosin under various conditions were analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. Purified samples of these species were digested under controlled conditions by chymotrypsin and trypsin and a comparison of the observed heavy chain fragmentation patterns led to a sequential arrangement of the proteolytic fragments. The main features of this arrangement are the following: a 21K molecular weight tryptic peptide is found at the N-terminal side of myosin heavy chain. Adjacent to it is a 48K peptide, then a 19.5K peptide containing the two SH-1 and SH-2 thiols. These three peptides constitute the heavy chain of S-1. Adjacent to this S-1 heavy chain is a tryptic (and also chymotryptic) 40K peptide. The rest of the HMM heavy chain on the C-terminus is a sequence susceptible to both chymotrypsin and trypsin attack yielding an undefined number of small peptides.     

Simultaneous achievement of accurate CT number and image quality improvement for myocardial perfusion CT at 320-MDCT volume scanning

PurposeTo investigate differences in image-to-image variations between full- and half-scan reconstruction on myocardial CT perfusion (CTP) study.MethodsUsing a cardiac phantom we performed ECG-gated myocardial CTP on a second-generation 320-multidetector CT volume scanner. The heart rate was set at 60 bpm; once per second for a total of 24 s were performed. CT images were acquired at 80- and 120 kVp and subjected to full- and half-scan reconstruction. On images acquired at the same slice level we then measured image-to-image variations, coefficients of variance (CV), and image noise.ResultsThe image-to-image variations with full- and half-scan reconstruction were 1.3 HU vs. 27.2 HU at 80 kVp (p < 0.001) and 0.70 HU vs. 9.3 HU at 120 kVp (p < 0.001) even though the mean HU value was almost the same for both reconstruction methods. The CV of 80- and 120-kVp images of the left ventricular cavity decreased by 0.16% and 0.17%, respectively, with full-scan reconstruction; with half-scan reconstruction it decreased by 3.34% and 2.30%, respectively. Compared with half-scan reconstruction, the image noise was reduced by 27.2% at 80 kVp and by 28.0% at 120 kVp with full-scan reconstruction.ConclusionMyocardial CTP with full-scan reconstruction substantially decreased image-to-image variations and provided accurate CT attenuation.     

CT与MRI扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用

摘要 目的：探讨电子计算机断层扫描(Computed Tomography,CT)与磁共振成像(Magnetic resonance imaging,MRI)扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用。方法：2016年9月到2019年10月选择在本院诊治的下拟诊为四肢骨关节隐匿性骨折118例,所有患者都给予CT与MRI扫描三维重建诊断,记录影像学特征与判断诊断价值。结果：在118例患者中,最终确诊为四肢骨关节隐匿性骨折98例,无骨折20例,其中腕关节骨折34例,踝关节骨折22例,膝关节骨折15例,肘关节骨折15例,肩关节骨折8例,髋关节骨折4例。在98例确诊的四肢骨关节隐匿性骨折中,MRI三维重建显示双边征、骨质破坏、充气征、软组织影等比例显著都高于CT (P<0.05)。CT与MRI三维重建诊断四肢骨关节隐匿性骨折的敏感性为89.8 %和99.0 %,特异性为95.0 %和100.0 %,误诊率分别为9.3 %和0.8 %,MRI三维重建诊断的敏感性高于CT ,漏诊率低于CT。结论：CT与MRI扫描三维重建在四肢骨关节隐匿性骨折诊断中的应用都有很好的价值,特别是MRI三维重建能清晰显示骨折特征,具有更高的诊断敏感性,能减少漏诊率,可作为四肢骨关节隐匿性骨折的首选检查方法。     

Enhanced regional terrestrial carbon uptake over Korea revealed by atmospheric CO2 measurements from 1999 to 2017

Understanding changes in terrestrial carbon balance is important to improve our knowledge of the regional carbon cycle and climate change. However, evaluating regional changes in the terrestrial carbon balance is challenging due to the lack of surface flux measurements. This study reveals that the terrestrial carbon uptake over the Republic of Korea has been enhanced from 1999 to 2017 by analyzing long‐term atmospheric CO₂ concentration measurements at the Anmyeondo Station (36.53°N, 126.32°E) located in the western coast. The influence of terrestrial carbon flux on atmospheric CO₂ concentrations (ΔCO₂) is estimated from the difference of CO₂ concentrations that were influenced by the land sector (through easterly winds) and the Yellow Sea sector (through westerly winds). We find a significant trend in ΔCO₂ of ?4.75 ppm per decade (p < .05) during the vegetation growing season (May through October), suggesting that the regional terrestrial carbon uptake has increased relative to the surrounding ocean areas. Combined analysis with satellite measured normalized difference vegetation index and gross primary production shows that the enhanced carbon uptake is associated with significant nationwide increases in vegetation and its production. Process‐based terrestrial model and inverse model simulations estimate that regional terrestrial carbon uptake increases by up to 18.9 and 8.0 Tg C for the study period, accounting for 13.4% and 5.7% of the average annual domestic carbon emissions, respectively. Atmospheric chemical transport model simulations indicate that the enhanced terrestrial carbon sink is the primary reason for the observed ΔCO₂ trend rather than anthropogenic emissions and atmospheric circulation changes. Our results highlight the fact that atmospheric CO₂ measurements could open up the possibility of detecting regional changes in the terrestrial carbon cycle even where anthropogenic emissions are not negligible.     

Higher patient doses through X-ray imaging procedures

Medical imaging using X-rays has been one of the most popular imaging modalities ever since the discovery of X-rays 125 years ago. With unquestionable benefits, concerns about radiation risks have frequently been raised. Computed tomography (CT) and fluoroscopic guided interventional procedures have the potential to impart higher radiation exposure to patients than radiographic examinations. Despite technological advances, there have been instances of increased doses per procedure mainly because of better diagnostic information in images. However, cumulative dose from multiple procedures is creating new concerns as effective doses >100 mSv are not uncommon. There is a need for action at all levels. Manufacturers must produce equipment that can provide a quality diagnostic image at substantially lesser dose and better implementation of optimization strategies by users. There is an urgent need for the industry to develop CT scanners with sub-mSv radiation dose, a goal that has been lingering. It appears that a new monochromatic X-ray source will lead to replacement of X-ray tubes all over the world in coming years and will lead to a drastic reduction in radiation doses. This innovation will impact all X-ray imaging and will help dose reduction. For interventional procedures, the likely employment of robotic systems in practice may drastically reduce radiation exposures to operators- but patient exposure will still remain an issue. Training needs always need to be emphasized and practiced.     

CT定量分析在冠心病介入治疗前后血流灌注改变的评估价值

摘要 目的：探讨CT定量分析在冠心病介入治疗前后血流灌注改变的评估价值。方法：2018年2月到2020年11月选择在本院诊治的冠心病患者95例作为研究对象,所有患者都给予经皮冠状动脉介入治疗,在介入前1 d与介入后1个月进行CT定量与超声检查,随访介入后6个月的冠状动脉再狭窄情况并进行相关性分析。结果：所有患者都顺利完成介入治疗,介入期无严重并发症发生。95例患者介入后1个月的左室射血分数(ejectionfraction,EF)、左室短轴缩短率(fractionalshortening,FS)高于介入前1 d(P<0.05),介入前后左室等容舒张时间(iso-volumicrelaxationtime,IVRT)对比差异无统计学意义(P>0.05)。95例患者介入后1个月的心肌血流量(Myocardialbloodflow,MBF)、心肌血容量(Myocardialbloodvolume,MBV)高于介入前1d(P<0.05),达峰时间(Timetopeak,TTP)低于介入前1 d(P<0.05)。介入后随访6个月,冠状动脉再狭窄14例,再狭窄率14.7 %,其中中度狭窄12例,重度狭窄2例;Pearson分析显示冠心病患者介入前1 d的MBF、MBV、TTP与FS、EF都存在相关性(P<0.05);Logistic回归分析显示MBF、MBV、TTP、FS、EF为影响冠心病患者介入后随访再狭窄率的重要因素(P<0.05)。结论：CT定量分析在冠心病介入前后的应用能有效反映血流灌注改变情况,且与患者的心功能存在相关性,也可有效预测患者介入随访冠状动脉再狭窄发生情况。