A cytochrome c oxidase proton pumping mechanism that excludes the O2 reduction site

A redox-coupled conformational change in Asp51 of subunit I and a hydrogen-bond network connecting Asp51 with the matrix surface have been deduced from X-ray structures of bovine heart cytochrome c oxidase. This has provided evidence that Asp51 may play a role in the proton pumping process. However, the lack of complete conservation of a residue analogous to Asp51, the inclusion of a peptide bond in the hydrogen-bonding network and the lack of apparent involvement of the O2 reduction site have been used as arguments against the involvement of Asp51 in the mechanism of proton pumping. This minireview re-examines these arguments.     

Field tests of a balloon-suspended trap system for studying insects in the canopy of tropical rainforests

A system of suspending traps from a movable balloon was developed and tested on pollinating and wood boring Coleoptera in a tropical rainforest canopy in Pasoh Forest Reserve, Peninsular Malaysia. The balloons, 2.5 m in diameter, were filled with helium gas for levitation and moored in different directions by three pieces of thin rope. Traps in which benzyl acetate and ethanol were used as attractants for the pollinators and wood borers, respectively, were suspended from the balloon at different heights. The trapping results show that the balloon system can be used for studying canopy insects and their vertical distribution on a spatial and temporal scale.     

The plasma membrane ATPase of Kloeckera apiculata: purification,characterization and effect of ethanol on activity

Partially (6-fold) purified plasma membrane ATPase from an ethanol-sensitive yeast, Kloeckera apiculata, had an optimum pH of 6.0, an optimum temperature of 35°C, a K _m of 3.6 mm ATP and a V _max of 11 mol P_i/min.mg protein. SDS-PAGE of the semi-purified plasma membrane showed a major band of 106 kDa. No in vivo activation of the ATPase by glucose was observed. Although 4% (v/v) ethanol decreased the growth rate by 50% it did not affect the ATPase. Concentrations of ethanol 2% (v/v) did, however, inhibit the enzyme in vitro. The characteristics of the enzyme did not change during growth in the presence of ethanol.     

Vacuolar pH oscillations in mesophyll cells accompany oscillations of photosynthesis in leaves: Interdependence of cellular compartments,and regulation of electron flow in photosynthesis

Oscillations of photosynthesis induced in leaves of Vicia faba L. were accompanied by oscillations not only in the pH of the chloroplast stroma, but also by pH oscillations in the cytosol and in the vacuole of leaf mesophyll cells. Cytosolic pH oscillations were in phase with stromal oscillations, but antiparallel to vacuolar pH oscillations. During maxima of photosynthesis, the cytosolic pH exhibited maxima and the vacuolar pH minima. Vacuolar acidification is interpreted to be the result of energized proton transport from the cytosol into the vacuole. Since the ratio of dihydroxyacetone phosphate to phosphoglycerate is maximal during the peaks of photosynthesis (Stitt et al., 1988, J. Plant Physiol. 133, 133–143; Laisk et al., 1991, Planta 185, 554–562), while the activity of NADP-malic dehydrogenase is highest during minima of photosynthesis (Scheibe and Stitt, 1988, Plant Physiol. Biochem. 26, 473–481), the present data indicate in agreement with earlier observations (Yin et al., 1991, Planta 184, 30–34) that light-dependent cytosolic energization is brought about by the oxidation of dihydroxyacetone phosphate rather than of malate. They also indicate that the over-reduction of the electrontransport chain observed during minima of photosynthesis is relieved not predominantly by oxaloacetate reduction and export of the resulting malate from the chloroplasts but by another reaction, presumably oxygen reduction.Abbreviations CDCF 5-(and 6-)carboxy-2,7-dichlorofluorescein     

Tyramine receptor (SER-2) isoforms are involved in the regulation of pharyngeal pumping and foraging behavior in Caenorhabditis elegans

Octopamine regulates essential processes in nematodes; however, little is known about the physiological role of its precursor, tyramine. In the present study, we have characterized alternatively spliced Caenorhabditis elegans tyramine receptor isoforms (SER-2 and SER-2A) that differ by 23 amino acids within the mid-region of the third intracellular loop. Membranes prepared from cells expressing either SER-2 or SER-2A bind [3H]lysergic acid diethylamide (LSD) in the low nanomolar range and exhibit highest affinity for tyramine. Similarly, both isoforms exhibit nearly identical Ki values for a number of antagonists. In contrast, SER-2A exhibits a significantly lower affinity than SER-2 for other physiologically relevant biogenic amines, including octopamine. Pertussis toxin treatment reduces affinity for both tyramine and octopamine, especially for octopamine in membranes from cells expressing SER-2, suggesting that the conformation of the mid-region of the third intracellular loop is dictated by G-protein interactions and is responsible for the differential tyramine/octopamine affinities of the two isoforms. Tyramine reduces forskolin-stimulated cAMP levels in HEK293 cells expressing either isoform with nearly identical IC50 values. Tyramine, but not octopamine, also elevates Ca2+ levels in cells expressing SER-2 and to a lesser extent SER-2A. Most importantly, ser-2 null mutants (pk1357) fail to suppress head movements while reversing in response to nose-touch, suggesting a role for SER-2 in the regulation of foraging behavior, and fail to respond to tyramine in assays measuring serotonin-dependent pharyngeal pumping. These are the first reported functions for SER-2. These results suggest that C. elegans contains tyramine receptors, that individual SER-2 isoforms may differ significantly in their sensitivity to other physiologically relevant biogenic amines, such as octopamine (OA), and that tyraminergic signaling may be important in the regulation of key processes in nematodes.     

Intra-aortic balloon counterpulsation in acute myocardial infarction: old and emerging indications

Background

Recent evidence questions the role of intra-aortic balloon counterpulsation (IABP) in the treatment of acute myocardial infarction (AMI) complicated by cardiogenic shock (CS). An area of increasing interest is the use of IABP for persistent ischaemia (PI). We analysed the use of IABP in patients with AMI complicated by CS or PI.

Methods

From 2008 to 2010, a total of 4076 patients were admitted to our hospital for primary percutaneous coronary intervention (PCI) for AMI. Out of those, 239 patients received an IABP either because of CS or because of PI. Characteristics and outcome of those patients are investigated.

Results

The mean age of the study population was 64 ± 11 years; 75 % were male patients. Of the patients, 63 % had CS and 37 % had PI. Patients with CS had a 30-day mortality rate of 36 %; 1-year mortality was 41 %. Patients with PI had a 30-day mortality rate of 7 %; 1-year mortality was 11 %.

Conclusions

Mortality in patients admitted for primary PCI because of AMI complicated by CS is high despite IABP use. Outcome in patients treated with IABP for PI is favourable and mandates further prospective studies.     

单球囊双侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折的效果分析

目的：探讨单球囊双侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折的临床疗效。方法：选取择期在我院接受单球囊双侧扩张椎体后凸成形术治疗骨质疏松性椎体压缩骨折的52例老年患者的临床资料,对患者的疼痛评分、椎体高度变化情况、术前和术后的后凸cobb角改善情况、术后复发情况等进行分析。结果：全部患者术后随访2-17个月,疼痛均得到缓解,术前VAS评分为8．6,术后VAS评分为2．5,差异具有统计学意义（P〈0．05）;平均椎体前缘高度恢复（56．5％±34％）,中部恢复（60．5％±35．4％）,后缘恢复（40．7％±32-3％）,矢状面排列改善明显（P〈0．05）;与术前相比,手术后患者侧位X片显示Cobb角平均改善10。（P〈0．05）。术后3例发生椎体前缘骨水泥渗漏,但未引起其他并发症;1例发生肋间神经痛,经保守治疗6个月后症状得到缓解。结论：单球囊zt-N扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折效果明显,值得临床推广。     

IABP在危重症冠状动脉旁路移植术围手术期的应用

目的：探讨危重症冠状动脉旁路移植术（CABG）患者围手术期应用主动脉球囊反搏（IABP）疗效。方法：回顾性分析2008年1月至2010年9月40例应用IABP治疗的危重症CABG患者围手术期资料。结果：术前安置IABP 19例,术中安置IABP 10例,术后安置IABP11例。平均IABP辅助时间98.6±48.2小时。32例患者治愈出院,死亡8例,死亡率20.0%。术前安置者死亡率为21.1%,若除外机械并发症原因则死亡率为10.5%;术中安置者死亡率为20.0%;术后安置者死亡率为18.2%。5例出现血小板减少症;1例出现肠系膜动脉栓塞。结论：IABP是一种安全有效的循环辅助方法,积极应用可以明显提高危重症CABG的治疗效果。     

Environmental DNA metabarcoding provides enhanced detection of the European eel Anguilla anguilla and fish community structure in pumped river catchments

The European eel Anguilla anguilla (eel hereafter) is critically endangered and has a catadromous life cycle, which means adult eels that live in pumped catchments must pass through pumps during their downstream spawning migration. Policy makers are currently lacking detailed site-by-site eel distribution information to estimate the overall impact of individual pumping stations on eel escapement, and as such lack the data to enable informed prioritisation of pumping station management and targeted mitigation. This study investigated whether environmental DNA (eDNA) metabarcoding can provide increased detection sensitivity for eel and fish community structure in highly regulated pumped catchments, when compared directly to current standard practice fish survey protocols (seine netting/electric fishing). Eels were detected in 14 of 17 sites (82.4%) using eDNA metabarcoding in contrast to 3 of 17 sites (17.6%) using traditional catch methods. In addition, when using eDNA monitoring, species richness was higher in 16 of 17 sites (94.1%), and site occupancy was greater than or equal to traditional methods for 23 of 26 of the fish species detected (88.5%). Although eDNA methods presented significantly higher average species richness and species site occupancy overall, eDNA and catch methods were positively correlated in terms of species richness and site occupancy. It was therefore found that eDNA metabarcoding was a high-sensitivity method for detecting eels in pumped catchments while also increasing the detection of overall fish community structure compared to traditional catch methods. In addition, this study highlights how eDNA monitoring is especially suited to increase the detection of particular species, with traditional methods sufficient for others. This high sensitivity, coupled with the ability to sample multiple sites in a short time frame, suggests that eDNA metabarcoding workflows could be invaluable tools when prioritising pumping station management.     

小切开EST联合EPBD与单纯EST对85岁以上老年胆总管结石患者疗效的比较

目的:对比内镜下十二指肠乳头括约肌(expressed sequence tags,EST)小切开术联合内镜下十二指肠乳头括约肌扩张术(endoscopic papillary balloon dilation,EPBD)与单纯EST对85岁以上老年胆总管结石患者的疗效。方法:选择我院于2014年1月～2020年2月收治的85岁以上老年胆总管结石患者150例,根据入院顺序随机分成两组,每组各75例,给予对照组单纯小切开EST术治疗,给予研究组小切开EST+EPBD术治疗。对比两组的一次取石成功率、机械碎石、结石复发率等指标;术中操作时间、术中出血量、住院天数、术后排便天数等临床指标;术后胆道感染、急性胰腺炎、高淀粉酶血症、术后腹痛等并发症的总发生率。结果:研究组一次取石成功率显著高于对照组,机械碎石、结石复发率均显著低于对照组(P0.05);研究组的术中操作时间、术中出血量、住院天数、术后排便天数均显著低于对照组(P0.05);研究组术后胆道感染、急性胰腺炎、高淀粉酶血症、术后腹痛、术后迟发性出血等并发症的总发生率为9.33%(7/75),显著低于对照组37.33%(28/75),差异具有统计学意义(P0.05)。结论:小切开EST联合EPBD对85岁以上老年胆总管结石患者的疗效显著,该方法可有改善患者临床指标,降低术后并发症发生率,值得推荐至临床广泛应用。