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Objective To investigate the effect of neurophysiological monitoring in extended endoscopic transsphenoidal surgery for cavernous sinus and clivus tumors. Methods We monitored the oculomotor nerve, trochlear nerve, trigeminal nerve and abducent nerve in 18 patients with cavernous sinus and clivus tumors by recording the free⁃electromyography (f⁃EMG) and triggered⁃electromyography (t⁃EMG) from August 2019 to December 2020. Two needle electrodes were inserted percutaneous into the levator palpebrae superioris muscle, superior oblique muscle, extraocular rectus muscle and masticatory muscle. To evaluate spontaneous muscle activity and complex muscle action potentials after cranial nerve stimulation. We evaluated the safety of cranial nerves and provided objective information for neurosurgeon. Results All the 18 patients with cavernous sinus and clivus tumors were treated by extended endoscopic transsphenoidal surgery, including 10 pituitary adenomas, 5 chordomas, 2 craniopharyngiomas and one cystic schwannoma. Total resection rate achieved 9/18, subtotal resection rate was 4/18, and partial resection rate was 5/18. There was no postoperative internal carotid artery (ICA) injury and cerebrospinal fluid leakage. A total of 20 oculomotor nerves, 3 trochlear nerves, 27 trigeminal nerves and 26 abducent nerves were recorded. There were one patient with left abducent nerve palsy and one patient with right abducent nerve paresis before surgery. The median follow⁃up time was 8.63 months, postoperative brain nerve injury occurred in 2 patients, the brain nerve injury rate was 2/18, all of which recovered 3 months after surgery. No patients with postoperative impaired trigeminal nerve function. Conclusions Monitoring of oculomotor nerve, trochlear nerve, trigeminal nerve and abducent nerve in extended endoscopic transsphenoidal surgery for cavernous sinus and clivus tumors is a safe and effective method. By monitoring and evaluating intraoperative f ⁃ EMG and t ⁃ EMG, neurosurgeons can adjust surgical procedures and strategies during tumor resection and reduce cranial nerve injuries.

Abstract Impending climate warming is expected to influence plant growth and distribution, and the distribution range limit of tree species is extremely sensitive to climate change. However, synchronous comparisons of responses of different tree species with overlapping ecological niches to climate at their distribution range limit in the same region have received little attention. In the present study, we assessed the discrepancy in radial growth responses of two dominant oak species to climate at their distribution range limit (southern range limit for Quercus mongolica, northern range limit for Quercus variabilis) in Beijing, China. Furthermore, growth–climate relationships were examined using linear mixed‐effects models, and growth trends up to the year 2100 were forecast based on future climate scenarios (RCP2.6 and RCP8.5). Our results indicated that there were no significant differences in the growth response to climate between Q. variabilis at its northern limit and Q. mongolica at its southern limit, and the growth of the two tree species was positively correlated with the minimum temperature and negatively correlated with the climatic moisture deficit of autumn. However, the growth response to climate variables varied at different sites. Additionally, the model forecast showed an increase in radial growth of Q. variabilis at its northern limit and Q. mongolica at its southern limit up to the end of the present century.

β-cyclodextrin butenate was synthesized by using N, N'-Carbonyldiimidazole (CDI) activating reagent and 4-Dimethylaminopyridine (DMAP) as catalyst. The best preparation condition of β-CD butenate was described as below: reaction temperature was 25°C, concentration of 2-butenoic acid was 450 mmol/L, concentration of DMAP was 12.5 mmol/L and reaction time was 20 minutes and at this condition the yield of β-CD butenate was 0.83 mmol/g. According to the results of FT-IR spectrum, NMR spectroscopy and HPLC-QTof-mass spectrum of β-CD butenate, there were four types β-CD butenate synthesized, which were β-CD-2-butenoic acid monoester, β-CD-2-butenoic acid diester, β-CD-2-butenoic acid triester and β-CD-2-butenoic acid tetraester, respectively. [ABSTRACT FROM AUTHOR]

Promoting passive buildings is of great significance in the large-scale development of China. In this study, system dynamics theory is used to divide the ramp-up of the passive construction system into four subsystems, including the market demand subsystem, the government policy subsystem, the developers' economic benefits subsystem, and energy conservation and environmental protection consciousness subsystem. The passive construction production promotion model is built, and analysis of each subsystem is conducted. Then, the internal relations of passive construction hoisting system of the output feedback loop are built to draw the stock flow chart. After that, the key factors influencing the passive construction propulsion are found, and a sensitivity analysis is conducted to propose several passive construction production promoting strategies. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Chemical investigation of Fritillaria verticillata Willd. led to the isolation of eight novel isosteroidal alkaloids (1—4, 6, 9—11) and four known alkaloids (5, 7—8, 12), including three unprecedented cis‐fused D/E (13α, 17α) cevanine alkaloids (1—3), one rarely cis‐fused E/F (22α) cevanine alkaloid (6), and one uncommon 5β‐jervine‐type isosteroidal alkaloid featuring a cis‐fused A/B ring moiety (11). In order to establish the structures of 1, the calculated NMR with DP4+ evaluation was applied from the plausible structure candidates. The characteristic proton signals for distinguishing D/E conjunction of cevanine alkaloids were summarized. In addition, some proton and carbon signals α to nitrogen in 6 and 7 are unobservable due to the 14N nuclear quadrupolar relaxation, based on the NMR experiments in different solvents, calculated NMR method and X‐ray technology, their structures were determined. The NMR characteristics of cevanine alkaloids to distinguish orientation of long‐pair on nitrogen atom with β‐hydroxyl at C‐20 were also concluded. The anti‐inflammatory effects of compounds 1 and 4 were evaluated in LPS‐activated RAW 264.7 macrophages. Compound 4 decreased LPS‐induced releases of IL‐1β and IL‐17α in RAW264.7 cells in a dose‐dependent manner. Further mechanistic study revealed that 4 suppressed the phosphorylation of IκBα and p65 subunit to regulate the NF‐κB signaling pathway. [ABSTRACT FROM AUTHOR]

Cerasus serrulata (Rosaceae) is an important flowering cherry resource which is valuable for developing new cultivars of flowering cherries. It is broadly distributed and possesses abundant variations. In this study, phylogeographic analysis was conducted to reveal the evolutionary history to better understand the genetic diversity and genetic structure of C. serrulata so as to provide more accurate molecular insights into better conservation and utilization of the germplasm resources. A total of 327 individuals from 18 wild populations were collected. Three chloroplast DNA (cpDNA) fragments (matK, trnD‐E, and trnS‐G) and the nuclear internal transcribed spacer (ITS) were utilized. The results showed a high genetic diversity at both species level and population level of C. serrulata. High genetic differentiation and the existence of the phylogeographic structure were detected. No significant expansion events were discovered. Two geographic lineages were inferred. One was confined to the Qinling Mountains and the Taihang Mountains. The other was from the Wuling Mountains to the Jiangnan Hilly Regions and then went northeast to the coast of Asia. In addition, some taxonomic treatments of the C. serrulata complex are discussed and reconsidered. Conservation and utilization strategies of wild C. serrulata germplasm resources were recommended. [ABSTRACT FROM AUTHOR]

A dicarboxylatopillar[5]arene (DCP5)-based coordination polymer, namely DCP5-EuxTby, with color-tunable emission and capable of nitroaromatic pollutant detection, has been designed and fabricated via a typical metal–ligand coordination approach. Due to its rigid skeleton and electron-rich cavity, DCP5 plays an important role in this multi-color framework, not only as a linker but also as a blue-color fluorescence donor. Intriguingly, the fluorescent color of DCP5-EuxTby can be tuned from green to red simply by mediating the molar ratio of Eu3+ : Tb3+ in the functional system. More importantly, a white-color emitting system, that is, DCP5-Eu1Tb3, is discovered when the ratio of Eu3+ : Tb3+ is 1 : 3, and the white-light emissive DCP5-Eu1Tb3 exhibits good detection performance toward nitroaromatic pollutants in a wide application field. We envision that this work will open a new avenue for the exploration of synthetic macrocycle-based new materials in the construction of new fluorescent sensors and detectors for environmental sustainability and bio-related fields. [ABSTRACT FROM AUTHOR]

Cerasus dielsiana (Rosaceae) is one of the most characteristic wild flowering cherry species endemic to subtropical China, with high conservation value from ornamental, economic, and ecological perspectives. To verify its spatial genetic structure and phylogeographic history, evaluation of nuclear (ITS) sequence variation in 203 individuals from 25 wild populations across its natural distribution ranges was conducted. High levels of ribotypes and nuclear diversity (Hd = 0.879 ± 0.012, π = 3.56 ± 0.16) were detected at the species level. Spatial analysis of molecular variation (SAMOVA), median-joining network and phylogenetic Neighbour-joining tree assigned the populations into four genetically distinct groups. Meanwhile, high levels of genetic differentiation among populations and strong phylogeographic patterns (Nst = 0.837 > Gst = 0.585; P < 0.05) were revealed based on the analysis of molecular variance (AMOVA). Results of neutrality tests, mismatch distribution analyses, Mantel test, barrier analyses, together with ecological niche modelling (ENM) simulation and BEAST analysis suggest a long-term demographic history (95% HPD: 3.64–8.83 Mya) of C. dielsiana, and at least three potential in situ glacial refugia as well as recent demographic expansion in eastern region have been detected. Collectively, we highlight that the combined effect of natural selection and random genetic drift under complex topography and palaeoclimatic oscillations since the Last Glacial Maximum (LGM) in subtropical China might have been the main driver to the species' allopatric differentiation. Scientific conservation and sustainable utilization for wild C. dielsiana germplasm resources were subsequently proposed. [ABSTRACT FROM AUTHOR]

The β-cyclodextrin-acrylamide (CDM-AM) copolymer was prepared from acrylamide and β-CD maleate (CDM) using 60Co γ-ray irradiation method. The optimized preparation conditions for the CDM-AM copolymer are as follows: CDM:AM mass ratio of 1:1; irradiation dose of 4 kGy; and using 20 mL of DMF water solution. The yield rate of CDM-AM was 75% in grams using these synthetic conditions. The effects of the CDM-AM copolymer on the solubility and fungicidal activity of natamycin (NM) and carbendazim (MBC) were investigated. The stability constant of NM·CDM-AM and MBC·CDM-AM complexes at 303 K were of 13,446.06 M−1 and 2595.3 M−1, respectively. The complexes were characterized using phase solubility diagrams, NMR spectra and FT-IR spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone. [ABSTRACT FROM AUTHOR]

In this work, a novel supramolecular π-gel has been constructed using a naphthalimide functionalized pillar[5]arene-based gelator (MP5). The gelator MP5 simultaneously contains a naphthalimide moiety as the π…π interaction site as well as a fluorophore. Interestingly, the MP5-based supramolecular π-gel (MP5-G) exhibits strong aggregation-induced emission (AIE). MP5-G exhibited good thermal-responsiveness, acid and base-responsiveness and cation and amino acid-responsiveness. Meanwhile, this supramolecular π-gel also shows selective fluorescence sensing for Fe3+via cation–π interactions with high selectivity and sensitivity, and the detection limit of MP5-G for Fe3+ is 6.06 × 10−8 M. Even more meaningfully, MP5-G could remove Fe3+ from water solution with excellent recyclability and ingestion capacity, and the Fe3+ removal rate can reach up to 99.8%. Furthermore, the Fe3+ coordinated supramolecular gel, MP5-FeG, shows selective fluorescence “turn-on” sensing for l-Cys. The detection limit of MP5-FeG for l-Cys is 1.0 × 10−8 M. Simultaneously, thin films based on these supramolecular gels were prepared, which were confirmed to be convenient test kits for detecting Fe3+ and l-Cys. In addition, these supramolecular π-gels could be used as sensitive ion sensors, sensitive logic gates and fluorescent display materials. [ABSTRACT FROM AUTHOR]

Misfire fault diagnosis is an important issue in on-board diagnosis (OBD) system, which has significant impacts on emissions, fuel consumption, and engine damage during vehicle movement. This study systematically reviews and summarizes the progress of misfire fault diagnosis methods, i.e., judgement basis, misfire diagnosis classification, and observer design. Finally, some perspectives on misfire fault diagnosis are also discussed. [ABSTRACT FROM AUTHOR]

CO2, N2OH4 and CH4 are important greenhouse gases, and soils in forest ecosystems are their important sources. Carya cathayensis is a unique tree species with seeds used for high-grade dry fruit and oil production. Understory vegetation management plays an important role in soil greenhouse gases emission of Carya cathayensis stands. A one-year in situ experiment was conducted to study the effects of understory removal on soil CO2, N2O and CH4 emissions in C. cathayensis plantation by closed static chamber technique and gas chromatography method. Soil CO2 flux had a similar seasonal trend in the understory removal and preservation treatments, which was high in summer and autumn, and low in winter and spring. N2O emission occurred mainly in summer, while CH4 emission showed no seasonal trend. Understory removal significantly decreased soil CO2 emission, increased N2O emission and CH4 uptake, but had no significant effect on soil water soluble organic carbon and microbial biomass carbon. The global warming potential of soil greenhouse gases emitted in the understory removal treatment was 15.12 t CO2-e • hm-2 • a-1, which was significantly lower than that in understory preservation treatment ( 17.04 t CO2-e • hm-2 • a-1). [ABSTRACT FROM AUTHOR]

Effect of biochar addition on soil CO2 efflux in a typical Chinese chestnut (Castanea mollissima) plantation in Lin'an, Zhejiang Province, China was investigated from July 2012 to July 2013 by the static closed chamber-GC technique. Soil temperature, soil moisture, WSOC and MBC concentrations were determined as well. Results showed that soil CO2 efflux exhibited a strong seasonal pattern. Compared with the control (without biochar application), the biochar treatment increased the soil CO2 efflux only in the first month since application, and then the effect diminished thereafter. There were no significant differences in the annual cumulative value of soil CO2 efflux between the biochar and control treatments. The annual mean value in soil MBC concentration (362 mg.kg-1) in the biochar treatment was higher than that (322 mg.kg-1) in the control. However, no significant difference in the soil WSOC concentration was found between the biochar and control treatments. Strong exponential relationships between soil temperature and soil CO2 efflux were observed regardless of the treatment and soil layer. The apparent temperature sensitivity (Q10) of soil CO2 efflux in the biochar treatment was higher than that in the control. Soil CO2 efflux was related to soil WSOC concentration but not with soil MBC or moisture content. To conclude, the application of bamboo leaf biochar did not affect the annual cumulative CO2 emission in the Chinese chestnut plantation but increased the Q10, and the CO2 efflux was predominantly controlled by the soil temperature and soil WSOC level. [ABSTRACT FROM AUTHOR]

In June 2011-June 2012, a fertilization experiment was conducted in a typical Castanea mollissima stand in Lin'an of Zhejiang Province, East China to study the effects of inorganic and organic fertilization on the soil CO2 flux and the relationships between the soil CO2 flux and environmental factors. Four treatments were installed, i. e. , no fertilization (CK), inorganic fertilization (IF), organic fertilization (OF), half organic plus half inorganic fertilization (OIF). The soil CO2 emission rate was determined by the method of static closed chamber/ GC technique, and the soil temperature, soil moisture content, and soil water-soluble organic carbon (WSOC) concentration were determined by routine methods. The soil CO2 emission exhibited a strong seasonal pattern, with the highest rate in July or August and the lowest rate in February. The annual accumulative soil CO2 emission in CK was 27. 7 t CO2 ·hm-2 ·a-1, and that in treatments IF, OF, and OIF was 29. 5%, 47. 0%, and 50. 7% higher than the CK, respectively. The soil WSOC concentration in treatment IF (105. 1 mg kg-1) was significantly higher than that in CK (76. 6 mg·kg-1), but was obviously lower than that in treatments OF (133. 0 mg·kg-1 ) and OIF (121. 2 mg·kg-1 ). The temperature sensitivity of respiration (Q10) in treatments CK, IF, OF, and OIF was 1. 47, 1. 75, 1. 49, and 1. 57, respectively. The soil CO2 emission rate had significant positive correlations with the soil temperature at the depth of 5 cm and the soil WSOC concentration, but no significant correlation with soil moisture content. The increase of the soil WSOC concentration caused by fertilization was probably one of the reasons for the increase of soil CO2 emission from the C. mollissima stand. [ABSTRACT FROM AUTHOR]

To investigate the effects of the conversion from native shrub forest (NF) to Chinese chestnut plantation (CP) on the soil carbon (C) and nitrogen (N) pools, soil samples were collected from the adjacent NF and CP in Anji County of Zhejiang Province, with their water-soluble organic C (WSOC), microbial biomass C (MBC), readily oxidizable C (ROC), water-soluble organic N (WSON), and microbial biomass N (MBN) determined. The spectral characteristics of soil organic C were also determined by using nuclear magnetic resonance (NMR) technique. After the conversion from NF to CP, the soil alkalyzable N, available phosphorus, and available potassium contents increased significantly, while the soil WSOC, MBC, ROC, WSON, and MBN were in adverse. The soil organic C in both NF and CP was dominated by alkyl C and O-alkyl C, but the proportions of O-alkyl C and carbonyl C in soil organic C decreased while the proportions of alkyl C and aromatic C as well as the alkyl C / O-alkyl C ratio and the aromaticity of soil organic C all increased significantly after the conversion from NF to CP, indicating that this conversion increased the stability of soil organic C pool significantly. In conclusion, the conversion from NF to CP and the intensive management of CP decreased the contents of soil labile C and soil N but increased the stability of soil C pool significantly. [ABSTRACT FROM AUTHOR]

Based on the 1974-2008 forest fire and meteorological data in Tahe County of Great Xing' an Mountains region, and with the help of Canadian Forest Fire Weather Index System ( CFFWIS) , this paper qualitatively and quantitatively analyzed the dynamics of forest fire weather indices in the region. In 1974-2008 , the mean annual fire occurrence in the region showed an increasing trend, and the increment in 2000-2008 was 72. 2% , compared with that in 1974-1999. The fuel moisture codes, fire behavior indices, and fire severity indices in 1974-2008 had an overall increasing trend, which was more evident with time extended. In the future, the probability of forest fire occurrence in the region would be increasing, fuels would be getting drier, fire intensity would be increased, fire weather would be more serious, and fire control would be more difficult. Therefore, more efforts should be made to improve the capability of forest fire control, especially in summer. As a fundamental technique, prescribed burning should be applied to reduce the fuel load. From this doing, the probability of fire occurrence and the fire potential intensity could be reduced. [ABSTRACT FROM AUTHOR]

The propagation and multiple scattering of non-homogeneous shear waves resulting from two cavities embedded in exponential functional graded materials (FGMs) were investigated, and the dynamic stress around the two cavities derived. The non-homogeneous scattering fields of shear waves around the cavities are analytically expressed by using the wave function expansion method. The interaction of non-homogeneous scattering fields between the two cavities is described accurately. The dynamic stresses around the cavities under different geometrical and physical parameters are graphically illustrated and analyzed. Analysis shows that the non-homogeneous properties of FGMs exhibit a significant effect on the dynamic stress around the cavities. The effect of the non-homogeneous properties of FGMs on the dynamic stress is also dependent on the gradation direction, the distance between the two cavities, the relative position of the two cavities and the incident frequency of waves. A comparison with other existing studies in the literature is also presented. [ABSTRACT FROM AUTHOR]

With two rice genotypes (cv. Zhongbu 51 and Azucena) differing in their root-secreted acid phosphatase activity (APA) under low P condition as test materials, an agar culture experiment was conducted to investigate their P utilization from myo-inositol hexaphosphate (IHP) under conditions of sterilization and inoculating with soil microorganisms. Under sterilization, the shoot dry mass, P absorption and P concentration of test genotypes supplied with hexaphosphate (IHP) as the P source were significantly higher than those with no P supply, but significantly lower than those supplied with inorganic P, indicating that rice plants could partly acquire P from IHP under sterilized condition. The root-secreted APA of the two genotypes was significantly higher under low P than under sufficient P supply, and the higher APA of Zhongbu 51 under low P could be one of the mechanisms of higher P utilization capability of Zhongbu 51 than Azucena under deficient P supply. When supplied with high level IHP (0.96 mmol P · L-1), the shoot dry mass, P absorption and P concentration of both Zhongbu 51 and Azucena were higher than those when supplied with low level IHP (0.16 mmol P · L-1), indicating that substrate availability could be one of the limiting factors to the utilization of phytate by rice. Inoculation with soil microorganisms had no significant effects on the shoot dry mass, P absorption and P concentration of rice plants, regardless of IHP level and rice genotypes, implying that the utilization of IHP by rice could not be improved via inoculation with soil microorganisms. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC), a major global cause of diarrhea, initiates the pathogenic process via fimbriae-mediated attachment to the small intestinal epithelium. A common prototypic ETEC fimbria, colonization factor antigen I (CFA/I), consists of a tip-localized minor adhesive subunit CfaE and the stalk-forming major subunit CfaB, both of which are necessary for fimbrial assembly. To elucidate the structure of CFA/I at atomic resolution, three recombinant proteins were generated consisting of fusions of the minor and major subunits (CfaEB) and of two (CfaBB) and three (CfaBBB) repeats of the major subunit. Crystals of CfaEB diffracted X-rays to 2.1 Å resolution and displayed the symmetry of space group P21. CfaBB exhibited a crystal diffraction limit of 2.3 Å resolution and had the symmetry of space group P21212. CfaBBB crystallized in the monoclinic space group C2 and diffracted X-rays to 2.3 Å resolution. These structures were determined using the molecular-replacement method. [ABSTRACT FROM AUTHOR]

l-2-Haloacid dehalogenase catalyzes the hydrolytic dehalogenation of l-2-haloalkanoic acids to produce the corresponding d-2-hydroxyalkanoic acids. Asp10 of l-2-haloacid dehalogenase from Pseudomonas sp. YL nucleophilically attacks the α-carbon atom of the substrate to form an ester intermediate, which is subsequently hydrolyzed by an activated water molecule. We previously showed that the replacement of Thr14, Arg41, Ser118, Lys151, Tyr157, Ser175, Asn177, and Asp180 causes significant loss in the enzyme activity, indicating the involvement of these residues in catalysis. In the present study, we tried to determine which process these residues are involved in by monitoring the formation of the ester intermediate by measuring the molecular masses of the mutant enzymes using ionspray mass spectrometry. When the wild-type enzyme and the T14A, S118D, K151R, Y157F, S175A, and N177D mutant enzymes were mixed with the substrate, the ester intermediate was immediately produced. In contrast, the R41K, D180N, and D180A mutants formed the intermediate much more slowly than the wild-type enzyme, indicating that Arg41 and Asp180 participate in the formation of the ester intermediate. This study presents a new method to analyze the roles of amino acid residues in catalysis. [Copyright &y& Elsevier]

Abstract Rotavirus gastroenteritis is an important pediatric disease in China. In a survey of rotavirus infection at two sentinel hospitals in China (Beijing Friendship Hospital and Changchun Children’s Hospital), 296 cases were detected. A total of 283 (95.6%) cases of rotavirus infection occurred in children under 5 years of age. Serotype G1 (62%) was most prevalent followed by G2 (28.5%), G3 (5%) and G4 (2%). Mixed infections (n=8, 3%) were rare, and 16 isolates (5.5%) remained non-typeable. A consistent epidemic occurred during the winter. Rotavirus was responsible for about 61.8% of diarrhea-related hospitalizations in children under 5 years of age, with a mean hospital stay of 5.6 days (1.0–21 days). The estimated rate of rotavirus-attributed hospitalizations was 16/1000 children under 5 years of age per year. Rotavirus-related death is rare in Changchun and Beijing. The present findings suggest that a rotavirus vaccine for the prevention of severe disease and a reduction of treatment costs would be of significant benefit to China. [ABSTRACT FROM AUTHOR]

In transportation cyber-physical-systems (T-CPS), vehicle-to-vehicle (V2V) communications play an important role in the coordination between individual vehicles as well as between vehicles and the roadside infrastructures, and engine cylinder pressure is significant for engine diagnosis on-line and torque control within the information exchange process under V2V communications. However, the parametric uncertainties caused from measurement noise in T-CPS lead to the dynamic performance deterioration of the engine cylinder pressure estimation. Considering the high accuracy requirement under V2V communications, a high gain observer based on the engine dynamic model is designed to improve the accuracy of pressure estimation. Then, the analyses about convergence, converge speed and stability of the corresponding error model are conducted using the Laplace and Lyapunov method. Finally, results from combination of Simulink with GT-Power based numerical experiments and comparisons demonstrate the effectiveness of the proposed approach with respect to robustness and accuracy. [ABSTRACT FROM AUTHOR]

Cytochrome bc1 is an integral membrane protein complex essential for cellular respiration and photosynthesis; it couples electron transfer from quinol to cytochrome c to proton translocation across the membrane. Specific bc1 inhibitors have not only played crucial roles in elucidating the mechanism of bc1 function but have also provided leads for the development of novel antibiotics. Crystal structures of bovine bc1 in complex with the specific Qo site inhibitors azoxystrobin, MOAS, myxothiazol, stigmatellin and 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole were determined. Interactions, conformational changes and possible mechanisms of resistance, specific to each inhibitor, were defined. Residues and secondary structure elements that are capable of discriminating different classes of Qo site inhibitors were identified for the cytochrome b subunit. Directions in the displacement of the cd1 helix of cytochrome b subunit in response to various Qo site inhibitors were correlated to the binary conformational switch of the extrinsic domain of the iron–sulfur protein subunit. The new structural information, together with structures previously determined, provide a basis that, combined with biophysical and mutational data, suggest a modification to the existing classification of bc1 inhibitors. bc1 inhibitors are grouped into three classes: class P inhibitors bind to the Qo site, class N inhibitors bind to the Qi site and the class PN inhibitors target both sites. Class P contains two subgroups, Pm and Pf, that are distinct by their ability to induce mobile or fixed conformation of iron–sulfur protein. [Copyright &y& Elsevier]