Kinesin-8 motors can move with a high processivity on microtubule lattices toward the plus end.After reaching the plus end,the kinesin-8 motors can pause for a long time and promote the microtubule depolymerization.He...Kinesin-8 motors can move with a high processivity on microtubule lattices toward the plus end.After reaching the plus end,the kinesin-8 motors can pause for a long time and promote the microtubule depolymerization.Here,using atomistic molecular dynamics simulations we studied the structural changes of the kinesin-8 head in different nucleotide states bound to the straight and curved tubulins and the corresponding interactions between them.We found that the kinesin-8 head in ATP and/or ADP–Pi state has the similar strong affinity while in ADP state has the similar weak affinity to both the straight and curved tubulins,which is strongly implicated in the mechanism of the long but very different residence times of the kinesin-8 motor on the microtubule lattice and at the end.Moreover,we found that loop-2 of the kinesin-8 head bound strongly to the curved tubulin in the stable state has a large interference with its neck linker pulled in the minusended orientation.This is contrary to the case of the head bound strongly to the straight tubulin,where loop-2 has little interference with its neck linker pulled in the minus-ended orientation.The large interference can induce a larger internal force between the two heads and thus can induce the two curved tubulins bound strongly by the two heads to be more curved relative to each other.This is strongly implicated in the mechanism of the depolymerase activity of the kinesin-8motors and explains the origin of loop-2 playing a facilitating role in the depolymerase activity.展开更多
BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically...BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.展开更多
Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination...Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.展开更多
Intracellular transports of cargoes are performed by biological molecular motors that move processively along their linear tracks.In some cases,the cargo can interact with the track.A typical example of these cases is...Intracellular transports of cargoes are performed by biological molecular motors that move processively along their linear tracks.In some cases,the cargo can interact with the track.A typical example of these cases is the transport of a major mitotic signaling module,the chromosomal passenger complex(CPC),along the microtubule toward the equatorial cortex by a kinesin-6 motor during anaphase,where the CPC can interact with the microtubule.Here,an analytical theory is presented on the dynamics of the molecular motor transporting a track-interacted cargo.The theory is then applied to the transport of the track-interacted cargo by kinesin-6 and by kinesin-1 motors,with the theoretical results reproducing quantitatively the available experimental data.It is found that a diffusive cargo along the track,with the diffusion constant≥0.1μm2s-1,can largely enhance the processivity relative to the non-diffusive cargo and relative to the cargo having no interaction with the track.展开更多
The lack of axonal regeneration is the major cause of vision loss after optic nerve injury in adult mammals. Activating the PI3K/AKT/mTOR signaling pathway has been shown to enhance the intrinsic growth capacity of ne...The lack of axonal regeneration is the major cause of vision loss after optic nerve injury in adult mammals. Activating the PI3K/AKT/mTOR signaling pathway has been shown to enhance the intrinsic growth capacity of neurons and to facilitate axonal regeneration in the central nervous system after injury. The deletion of the mTOR negative regulator phosphatase and tensin homolog （PTEN） enhances regeneration of adult corticospinal neurons and ganglion cells. In the present study, we used a tyrosine-mutated （Y444F） AAV2 vector to efficiently express a short hairpin RNA （shRNA） for silencing PTEN expression in retinal ganglion cells. We evaluated cell survival and axonal regeneration in a rat model of optic nerve axotomy. The rats received an intravitreal injection of wildtype AAV2 or Y444F mutant AAV2 （both carrying shRNA to PTEN） 4 weeks before optic nerve axotomy. Compared with the wildtype AAV2 vector, the Y444F mutant AAV2 vector enhanced retinal ganglia cell survival and stimulated axonal regeneration to a greater extent 6 weeks after axotomy. Moreover,post-axotomy injection of the Y444F AAV2 vector expressing the shRNA to PTEN rescued ～19% of retinal ganglion cells and induced axons to regenerate near to the optic chiasm. Taken together, our results demonstrate that PTEN knockdown with the Y444F AAV2 vector promotes retinal ganglion cell survival and stimulates long-distance axonal regeneration after optic nerve axotomy. Therefore, the Y444F AAV2 vector might be a promising gene therapy tool for treating optic nerve injury.展开更多
AIM: To evaluate the safety, quality and prospects of day-case cataract surgery performed in a Jiangsu public tertiary hospital METHODS: The general and clinical data for patients who underwent day-case cataract surge...AIM: To evaluate the safety, quality and prospects of day-case cataract surgery performed in a Jiangsu public tertiary hospital METHODS: The general and clinical data for patients who underwent day-case cataract surgery between August 1, 2014 and December 31, 2016 at this hospital were collected. The incidences of intraoperative and postoperative complications, preoperative and postoperative bestcorrected visual acuities(BCVAs), delayed discharge rate, rate of unplanned re-admission to hospital, and patient satisfaction were analyzed. RESULTS: A total of 4151 patients received cataract phacoemulsification surgery to correct age-related, congenital, traumatic, or complicated cataracts. Of these, age-related cataracts were the most frequently occurring. Patient age ranged from 18 to 101 y and the vast majority of patients were between 60 and 80 years old. Of the 4151 patients, 64.73%(2687/4151) had a systemic disease. The number of patients increased over the years, with the average number of patients per month being 90.4, 124.83, and 183.42 in 2014, 2015 and 2016, respectively. The average preoperative BCVA was 0.102±0.057 and average postoperative BCVAs at 1 d, 1 wk, and 1 mo post surgery were 0.453±0.264, 0.657±0.285, and 0.734±0.244, respectively. For intraoperative complications, 4.12%(171/4151) had posterior capsule rupture, 0.79%(33/4151) had iris or ciliary body injury, and 0.048%(2/4151) had suprachoroidal hemorrhage. For postoperative complications, 4.38%(182/4151) had cornea edema, 7.78%(323/4151) had intraocular hypertension, 0.096%(4/4151) had IOL toxicity syndrome, 0.28%(12/4151) had retained lens cortex, and 0.048%(2/4151) had hyphema. The delayed discharge rate was 0.82%(44/4151) and the unplanned re-admission to the hospital was 0(0/4151). The patient satisfaction rate was 91.42%(3795/4151). CONCLUSION: Day-case cataract surgery is safe and effective with good prospects for development.展开更多
The performance of traditional vibration based fault diagnosis methods greatly depends on those hand- crafted features extracted using signal processing algo- rithms, which require significant amounts of domain knowle...The performance of traditional vibration based fault diagnosis methods greatly depends on those hand- crafted features extracted using signal processing algo- rithms, which require significant amounts of domain knowledge and human labor, and do not generalize well to new diagnosis domains. Recently, unsupervised represen- tation learning provides an alternative promising solution to feature extraction in traditional fault diagnosis due to its superior learning ability from unlabeled data. Given that vibration signals usually contain multiple temporal struc- tures, this paper proposes a multiscale representation learning （MSRL） framework to learn useful features directly from raw vibration signals, with the aim to capture rich and complementary fault pattern information at dif- ferent scales. In our proposed approach, a coarse-grained procedure is first employed to obtain multiple scale signals from an original vibration signal. Then, sparse filtering, a newly developed unsupervised learning algorithm, is applied to automatically learn useful features from each scale signal, respectively, and then the learned features at each scale to be concatenated one by one to obtain multi- scale representations. Finally, the multiscale representa- tions are fed into a supervised classifier to achieve diagnosis results. Our proposed approach is evaluated using two different case studies： motor bearing and wind turbine gearbox fault diagnosis. Experimental results show that the proposed MSRL approach can take full advantages of the availability of unlabeled data to learn discriminative features and achieved better performance with higher accuracy and stability compared to the traditional approaches.展开更多
Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We rece...Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We recently identified zona pellucida(Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs,suggesting that Zp protein may play important roles in the regulation of egg type.In this work,we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow(Gobiocypris rarus),an East Asian cyprinid laying adhesive eggs,was driven by a zebrafish zp3.2 gene promoter.We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy.Abnormal metabolism of vitellogenin(VTG) may contribute to enhanced hydration and/or buoyancy.Our work shows that expression of the exogenous zp3a gene from an adhesiveegg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish,emphasizing the important role of zp genes in the regulation of spawning habits.Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.展开更多
Objective To investigate the hispathological characteristics and antioxidant responses in liver of silver carp after intraperitoneal administration of microcystins(MCs)for further understanding hepatic intoxication an...Objective To investigate the hispathological characteristics and antioxidant responses in liver of silver carp after intraperitoneal administration of microcystins(MCs)for further understanding hepatic intoxication and antioxidation mechanism in fish.Methods Phytoplanktivorous silver carp was injected intraperitoneally(i.p.)with extracted hepatotoxic microcystins(mainly MC-RR and-LR)at a dose of 1000μg MC-LReq./kg body weight,and liver histopathological changes and antioxidant responses were studied at 1,3,12,24,and 48 h,respectively,after injection.Results The damage to liver structure and the activities of hepatic antioxidant enzymes including catalase(CAT),superoxide dismutase(SOD),and glutathione peroxide(GPX)were increased in a time-dependent manner.Conclusion In terms of clinical and histological signs of intoxication and LD50(i.p.)dose of MC-LR,silver carp appears rather resistant to MCs exposure than other fishes.Also the significantly increased SOD activity in the liver of silver carp suggests a higher degree of response to MCs exposure than CAT and GPX.展开更多
Objective To investigate the efficacy of hematopoietic stem cell （HSC） transplantation via the hepatic artery vs. the portal vein for end-stage liver disease （ESLD）. Methods Patients with hepatic decompensation w...Objective To investigate the efficacy of hematopoietic stem cell （HSC） transplantation via the hepatic artery vs. the portal vein for end-stage liver disease （ESLD）. Methods Patients with hepatic decompensation were prospectively recruited from September 2010 to September 2012 to receive HSC transplantation via the hepatic artery or the portal vein. Liver function was examined at 3, 6, and 12 months after transplantation. Liver biopsy results were analyzed using the Knodell score. Results Eighty patients （58 males and 22 females） were enrolled in the study. The Child-Pugh score was grade B in 69 cases, and grade C in the remaining 11 cases. HSC transplantation was performed via the portal vein in 36 patients and via the hepatic artery in 44 patients. ALT levels decreased while serum albumin levels increased significantly in both groups at 6 and 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation levels）. Total biliruhin levels decreased significandy in both groups at 3, 6, and 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation levels）. Additionally, prothromhin time decreased in both groups at 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation level）. There were no significant differences in ALT, total bilirubin and prothromhin time between the two groups either before or after transplantation. Moreover, Knodell score decreased significantly at 6 and 12 months. Histological examination showed that liver cell edema, degeneration, necrosis, and inflammation were significantly relieved at 3, 6, and 12 months after transplantation. The incidence of portal vein thrombosis, upper gastrointestinal bleeding, and hepatic encephalopathy were 1.25%, 3.75%, and 2.5% respectively. The one-year survival rate was 100%. Conclusions Autologous HSC transplantation improves liver function and histology in ESLD patients The administration route of HSC has no significant impact on the efficacy of transplantation.展开更多
We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase cha...We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） fingerprinting. Chemical analysis and nitrogen dynamic changes illustrated that NH4＋-N was nitrified to NO2^--N and NO3^--N by bacterioplankton. Finally, NHa^＋-N was exhausted and NO3^--N was denitrified to NO2^--N, while the accumulation of NO2^--N indicated that bacterioplankton with completely aerobic denitrification ability were lacking in the water samples collected from Lake Taihu. We suggested that adding completely aerobic denitrification bacteria （to denitrify NO2^--N to N2） would improve the water quality. PCR-DGGE and sequencing results showed that more than 1/3 of the bacterial species were associated with the removal of nitrogen, and Acidovorax temperans was the dominant one. PCR-DGGE, variation of nitrogen, removal efficiencies of chlorophyll-a and canonical correspondence analysis indicated that the bacterioplankton significantly influenced the physiological and biochemical changes of cyanobacteria. Additionally, the unweighted pair-group method with arithmetic means revealed there was no obvious harm to the microecosystem from aeration. The present study demonstrated that bacterioplankton can play crucial roles in aerated ecosystems, which could control the impact of cyanobacterial blooms in eutrophicated fresh water systems.展开更多
AIM:To explore retinal displacement after surgical treatment for idiopathic macular hole(IMH)with different internal limiting membrane(ILM)peeling patterns.METHODS:Totally 22 eyes from 20 patients with IMH were random...AIM:To explore retinal displacement after surgical treatment for idiopathic macular hole(IMH)with different internal limiting membrane(ILM)peeling patterns.METHODS:Totally 22 eyes from 20 patients with IMH were randomly allocated into two groups,N-T group(11 eyes)and T-N group(11 eyes).For patients in N-T group,ILM was peeled off from nasal to temporal retina.For patients in T-N group,ILM was peeled off from temporal to nasal retina.Preoperative,postoperative 1,3,and 6 mo,autofluorescence fundus images were collected for manual measurement of distances of fixed nasal(N),temporal(T),superior(S),and inferior(I)retinal points(bifurcation or crossing of retinal vessels)around the macula to the optic disc(OD).These were respectively defined as N-OD,T-OD,S-OD,and I-OD.The retinal displacement,macular holeclosure rate,and best corrected visual acuity(BCVA)were compared between the two groups after surgery.RESULTS:At postoperative 1,3,and 6 mo,the macula slipped toward the OD,manifested by the decreased T-OD,N-OD,S-OD,and I-OD(P<0.05).No significant difference was found in the T-OD,N-OD,S-OD,and I-OD between N-T group and T-N group.IMH closure rate was 100%both in N-T group and T-N group.There was no significant difference in BCVA between two groups(P<0.05).CONCLUSION:The macula slips toward the OD after successful macular hole surgery.The two different ILM peeling pattern show similar visual outcome and retinal displacement,which means ILM peeling directions are not the influencing factor of postoperative retinal displacement.展开更多
A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by 1H-NMR and MS.
Sodium-ion batteries are promising candidates for large-scale grid storage systems and other applications.Their foremost advantage derives from superior environmental credentials,enhanced safety as well as lower raw m...Sodium-ion batteries are promising candidates for large-scale grid storage systems and other applications.Their foremost advantage derives from superior environmental credentials,enhanced safety as well as lower raw material costs than lithium-ion batteries.It is still challenging to explore desirable anode material.In this study,FeSe_(2)@CoSe_(2)/FeSe_(2),with a yolk-shell structure was prepared by ion exchange and selenisation.The FeSe_(2)@CoSe_(2)/FeSe_(2)prepared as anode material for sodiumion batteries exhibits excellent rate capability due to the synergistic effect of bimetallic selenides and the interfacial effect of the heterostructure.Moreover,it delivers high performance(510 mAh g^(-1)at 0.2 A g^(-1)),superior rate capa-bility(90%retention at 5 A g^(-1)),and good long-time cycling stability(78%capacity retention after 1800 cycles at a high current density of 2 A g^(-1)).The optimized sodiumion full cell with FeSe_(2)@CoSe_(2)/FeSe_(2)as the anode and Na 3 V 2(PO 4)3 as the cathode still demonstrates excellent performance.Namely,a ca-pacity of 272 mAh g^(-1)(at 1 A g^(-1))within the operating voltage from 1 to 3.8 V can be obtained.This work illustrates the potential of bimetallic selenides with heterostructures for performance enhancement of sodium-ion batteries.展开更多
The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water qualit...The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide （DMS）,dimethyl trisulfide （DMTS）,and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium （NH4＋-N） were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobacterial blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu.展开更多
The development of cloud computing and virtualization technology has brought great challenges to the reliability of data center services.Data centers typically contain a large number of compute and storage nodes which...The development of cloud computing and virtualization technology has brought great challenges to the reliability of data center services.Data centers typically contain a large number of compute and storage nodes which may fail and affect the quality of service.Failure prediction is an important means of ensuring service availability.Predicting node failure in cloud-based data centers is challenging because the failure symptoms reflected have complex characteristics,and the distribution imbalance between the failure sample and the normal sample is widespread,resulting in inaccurate failure prediction.Targeting these challenges,this paper proposes a novel failure prediction method FP-STE(Failure Prediction based on Spatio-temporal Feature Extraction).Firstly,an improved recurrent neural network HW-GRU(Improved GRU based on HighWay network)and a convolutional neural network CNN are used to extract the temporal features and spatial features of multivariate data respectively to increase the discrimination of different types of failure symptoms which improves the accuracy of prediction.Then the intermediate results of the two models are added as features into SCSXGBoost to predict the possibility and the precise type of node failure in the future.SCS-XGBoost is an ensemble learning model that is improved by the integrated strategy of oversampling and cost-sensitive learning.Experimental results based on real data sets confirm the effectiveness and superiority of FP-STE.展开更多
AIM： To estimate the effectiveness of phacoemulsification and foldable intraocular lens（IOL） implantation combined with transpupillary silicone oil removal.METHODS： There were 168 eyes of 168 candidate patients wi...AIM： To estimate the effectiveness of phacoemulsification and foldable intraocular lens（IOL） implantation combined with transpupillary silicone oil removal.METHODS： There were 168 eyes of 168 candidate patients with cataract and silicone oil-filled eyes recruited in our study. All of the patients received the intraocular silicone oil removal surgery by transpupillary drainage and cataract extraction by phacoemulsification. Then the IOL implantation were also performed through corneal incision. RESULTS： The surgery was successfully completed in all eyes. Best corrected visual acuity（BCVA） and postoperative complications were recorded in three months after surgery. There were 143 eyes with BCVA improved, otherwise 25 eyes remained stable at the last follow-up visit. The mean BCVA statistically improved from 20/400±0.02 to 20/100±0.15（P〈0.001） and mean postoperative IOP was 13.85±2.18 mm Hg（P=0.415）. No intra-operative complications were reported.CONCLUSION： Phacoemulsification combined with transpupillary removal of silicone oil is a safe and simple effective method. In general, it enables quick recovery of visual acuity with less complication rate.展开更多
Ultraviolet（UV） radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. O...Ultraviolet（UV） radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization＇s measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.展开更多
We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. G...We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.展开更多
基金Project supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202504529)the General Program of Chongqing Natural Science Foundation(Grant No.CSTB2025NSCQ-GPX0833)。
文摘Kinesin-8 motors can move with a high processivity on microtubule lattices toward the plus end.After reaching the plus end,the kinesin-8 motors can pause for a long time and promote the microtubule depolymerization.Here,using atomistic molecular dynamics simulations we studied the structural changes of the kinesin-8 head in different nucleotide states bound to the straight and curved tubulins and the corresponding interactions between them.We found that the kinesin-8 head in ATP and/or ADP–Pi state has the similar strong affinity while in ADP state has the similar weak affinity to both the straight and curved tubulins,which is strongly implicated in the mechanism of the long but very different residence times of the kinesin-8 motor on the microtubule lattice and at the end.Moreover,we found that loop-2 of the kinesin-8 head bound strongly to the curved tubulin in the stable state has a large interference with its neck linker pulled in the minusended orientation.This is contrary to the case of the head bound strongly to the straight tubulin,where loop-2 has little interference with its neck linker pulled in the minus-ended orientation.The large interference can induce a larger internal force between the two heads and thus can induce the two curved tubulins bound strongly by the two heads to be more curved relative to each other.This is strongly implicated in the mechanism of the depolymerase activity of the kinesin-8motors and explains the origin of loop-2 playing a facilitating role in the depolymerase activity.
基金Supported by the Gansu Provincial Science and Technology Plan Project,No.24JRRA886 and No.23JRRA1287Gansu Provincial People’s Hospital:Excellent Doctoral Student Cultivation Program,No.22GSSYD-14.
文摘BACKGROUND Noonan syndrome is a relatively common autosomal dominant genetic disorder characterized by cardiovascular defects owing to functional abnormalities in key genes such as RAF1.Mutations in RAF1 are typically associated with hypertrophic cardiomyopathy(HCM).However,in this case,the patient exhibited atrial and ventricular septal defects(VSDs).CASE SUMMARY This case report describes an 11-year-old boy diagnosed with Noonan syndrome,in whom genetic testing revealed a c.770C>T(p.Ser257 Leu)mutation in RAF1.The patient presented with intermittent chest discomfort and shortness of breath,symptoms that significantly worsened after physical activity.Clinical evaluation revealed marked growth retardation and multiple physical abnormalities.Electrocardiographic and echocardiographic assessments revealed VSDs,atrial septal defects,and left ventricular outflow tract obstruction.Following multidisciplinary consultation,the patient underwent cardiac surgical intervention,which led to clinical improvement;however,they subsequently developed a third-degree atrioventricular block,necessitating the implantation of a permanent pacemaker.During follow-up,echocardiographic findings demonstrated near-complete resolution of the shunt across the atrial and ventricular septa,significant improvement in left ventricular outflow tract obstruction,and notable reduction in ventricular septal thickness.A genetic mutation at the c.770C>T(p.Ser257 Leu)locus of RAF1 is typically associated with HCM and pulmonary hypertension.However,this patient’s clinical phenotype manifested as HCM,atrial septal defect,and VSD,suggesting that this mutation may involve a different pathophysiological mechanism.CONCLUSION This case confirms the genotype-phenotype heterogeneity of Noonan syndrome and highlights the complex management requirements of RAF1 mutation-associated cardiac pathologies.Early surgical intervention can ameliorate structural defects,but it must be integrated with genetic counseling and lifelong monitoring to optimize patient outcomes.
基金Project supported by Youth Project of Science and Technology Research Program of Chongqing Education Commission of China (Grant No. KJQN202404522)。
文摘Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubuleattachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data,we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.
基金supported by the Youth Project of Science and Technology Research Program of Chongqing Education Commission of China(No.KJQN202404522)。
文摘Intracellular transports of cargoes are performed by biological molecular motors that move processively along their linear tracks.In some cases,the cargo can interact with the track.A typical example of these cases is the transport of a major mitotic signaling module,the chromosomal passenger complex(CPC),along the microtubule toward the equatorial cortex by a kinesin-6 motor during anaphase,where the CPC can interact with the microtubule.Here,an analytical theory is presented on the dynamics of the molecular motor transporting a track-interacted cargo.The theory is then applied to the transport of the track-interacted cargo by kinesin-6 and by kinesin-1 motors,with the theoretical results reproducing quantitatively the available experimental data.It is found that a diffusive cargo along the track,with the diffusion constant≥0.1μm2s-1,can largely enhance the processivity relative to the non-diffusive cargo and relative to the cargo having no interaction with the track.
基金supported by the Research Foundation of Jiangsu Provincial Commission of Health and Family Planning of China,No.H201653the Research Foundation of Changshu Science and Technology Bureau of China,No.CS201616
文摘The lack of axonal regeneration is the major cause of vision loss after optic nerve injury in adult mammals. Activating the PI3K/AKT/mTOR signaling pathway has been shown to enhance the intrinsic growth capacity of neurons and to facilitate axonal regeneration in the central nervous system after injury. The deletion of the mTOR negative regulator phosphatase and tensin homolog （PTEN） enhances regeneration of adult corticospinal neurons and ganglion cells. In the present study, we used a tyrosine-mutated （Y444F） AAV2 vector to efficiently express a short hairpin RNA （shRNA） for silencing PTEN expression in retinal ganglion cells. We evaluated cell survival and axonal regeneration in a rat model of optic nerve axotomy. The rats received an intravitreal injection of wildtype AAV2 or Y444F mutant AAV2 （both carrying shRNA to PTEN） 4 weeks before optic nerve axotomy. Compared with the wildtype AAV2 vector, the Y444F mutant AAV2 vector enhanced retinal ganglia cell survival and stimulated axonal regeneration to a greater extent 6 weeks after axotomy. Moreover,post-axotomy injection of the Y444F AAV2 vector expressing the shRNA to PTEN rescued ～19% of retinal ganglion cells and induced axons to regenerate near to the optic chiasm. Taken together, our results demonstrate that PTEN knockdown with the Y444F AAV2 vector promotes retinal ganglion cell survival and stimulates long-distance axonal regeneration after optic nerve axotomy. Therefore, the Y444F AAV2 vector might be a promising gene therapy tool for treating optic nerve injury.
文摘AIM: To evaluate the safety, quality and prospects of day-case cataract surgery performed in a Jiangsu public tertiary hospital METHODS: The general and clinical data for patients who underwent day-case cataract surgery between August 1, 2014 and December 31, 2016 at this hospital were collected. The incidences of intraoperative and postoperative complications, preoperative and postoperative bestcorrected visual acuities(BCVAs), delayed discharge rate, rate of unplanned re-admission to hospital, and patient satisfaction were analyzed. RESULTS: A total of 4151 patients received cataract phacoemulsification surgery to correct age-related, congenital, traumatic, or complicated cataracts. Of these, age-related cataracts were the most frequently occurring. Patient age ranged from 18 to 101 y and the vast majority of patients were between 60 and 80 years old. Of the 4151 patients, 64.73%(2687/4151) had a systemic disease. The number of patients increased over the years, with the average number of patients per month being 90.4, 124.83, and 183.42 in 2014, 2015 and 2016, respectively. The average preoperative BCVA was 0.102±0.057 and average postoperative BCVAs at 1 d, 1 wk, and 1 mo post surgery were 0.453±0.264, 0.657±0.285, and 0.734±0.244, respectively. For intraoperative complications, 4.12%(171/4151) had posterior capsule rupture, 0.79%(33/4151) had iris or ciliary body injury, and 0.048%(2/4151) had suprachoroidal hemorrhage. For postoperative complications, 4.38%(182/4151) had cornea edema, 7.78%(323/4151) had intraocular hypertension, 0.096%(4/4151) had IOL toxicity syndrome, 0.28%(12/4151) had retained lens cortex, and 0.048%(2/4151) had hyphema. The delayed discharge rate was 0.82%(44/4151) and the unplanned re-admission to the hospital was 0(0/4151). The patient satisfaction rate was 91.42%(3795/4151). CONCLUSION: Day-case cataract surgery is safe and effective with good prospects for development.
基金Supported by Hebei Provincial Natural Science Foundation of China(Grant No.F2016203421)
文摘The performance of traditional vibration based fault diagnosis methods greatly depends on those hand- crafted features extracted using signal processing algo- rithms, which require significant amounts of domain knowledge and human labor, and do not generalize well to new diagnosis domains. Recently, unsupervised represen- tation learning provides an alternative promising solution to feature extraction in traditional fault diagnosis due to its superior learning ability from unlabeled data. Given that vibration signals usually contain multiple temporal struc- tures, this paper proposes a multiscale representation learning （MSRL） framework to learn useful features directly from raw vibration signals, with the aim to capture rich and complementary fault pattern information at dif- ferent scales. In our proposed approach, a coarse-grained procedure is first employed to obtain multiple scale signals from an original vibration signal. Then, sparse filtering, a newly developed unsupervised learning algorithm, is applied to automatically learn useful features from each scale signal, respectively, and then the learned features at each scale to be concatenated one by one to obtain multi- scale representations. Finally, the multiscale representa- tions are fed into a supervised classifier to achieve diagnosis results. Our proposed approach is evaluated using two different case studies： motor bearing and wind turbine gearbox fault diagnosis. Experimental results show that the proposed MSRL approach can take full advantages of the availability of unlabeled data to learn discriminative features and achieved better performance with higher accuracy and stability compared to the traditional approaches.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB31000000)。
文摘Reproductive strategies and spawning habits play key roles in the evolution of endemic East Asian cyprinids.However,the molecular mechanisms underlying the regulation of spawning habits are not well understood.We recently identified zona pellucida(Zp) as the top differentially expressed protein between East Asian cyprinids that produce adhesive and semi-buoyant eggs,suggesting that Zp protein may play important roles in the regulation of egg type.In this work,we generated transgenic zebrafish in which oocyte-specific expression of zp genes from rare minnow(Gobiocypris rarus),an East Asian cyprinid laying adhesive eggs,was driven by a zebrafish zp3.2 gene promoter.We found that the transgenic eggs obtained partial adhesiveness and exhibited alteration in hydration and buoyancy.Abnormal metabolism of vitellogenin(VTG) may contribute to enhanced hydration and/or buoyancy.Our work shows that expression of the exogenous zp3a gene from an adhesiveegg producing fish is sufficient to induce changes in both egg adhesiveness and buoyancy in zebrafish,emphasizing the important role of zp genes in the regulation of spawning habits.Our results thus provide new insights into how endemic East Asian cyprinids may have adapted to the Yangtze river-lake system via changes in spawning habits.
基金supported by the Key Project of CAS titled"The effects of regenerative organic pollutant microcystins on the safety of aquatic food"the National Natural Science Foundation of China(No.30700077)
文摘Objective To investigate the hispathological characteristics and antioxidant responses in liver of silver carp after intraperitoneal administration of microcystins(MCs)for further understanding hepatic intoxication and antioxidation mechanism in fish.Methods Phytoplanktivorous silver carp was injected intraperitoneally(i.p.)with extracted hepatotoxic microcystins(mainly MC-RR and-LR)at a dose of 1000μg MC-LReq./kg body weight,and liver histopathological changes and antioxidant responses were studied at 1,3,12,24,and 48 h,respectively,after injection.Results The damage to liver structure and the activities of hepatic antioxidant enzymes including catalase(CAT),superoxide dismutase(SOD),and glutathione peroxide(GPX)were increased in a time-dependent manner.Conclusion In terms of clinical and histological signs of intoxication and LD50(i.p.)dose of MC-LR,silver carp appears rather resistant to MCs exposure than other fishes.Also the significantly increased SOD activity in the liver of silver carp suggests a higher degree of response to MCs exposure than CAT and GPX.
基金Supported by the Science&Technology Department of Sichuan Province(2010FZ0098,2011HH0022)Chengdu Bureau of Science and Technology(10GGYB883SF)the Scientific Research Foundation of the Health Department of Sichuan Province(100487,100489)
文摘Objective To investigate the efficacy of hematopoietic stem cell （HSC） transplantation via the hepatic artery vs. the portal vein for end-stage liver disease （ESLD）. Methods Patients with hepatic decompensation were prospectively recruited from September 2010 to September 2012 to receive HSC transplantation via the hepatic artery or the portal vein. Liver function was examined at 3, 6, and 12 months after transplantation. Liver biopsy results were analyzed using the Knodell score. Results Eighty patients （58 males and 22 females） were enrolled in the study. The Child-Pugh score was grade B in 69 cases, and grade C in the remaining 11 cases. HSC transplantation was performed via the portal vein in 36 patients and via the hepatic artery in 44 patients. ALT levels decreased while serum albumin levels increased significantly in both groups at 6 and 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation levels）. Total biliruhin levels decreased significandy in both groups at 3, 6, and 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation levels）. Additionally, prothromhin time decreased in both groups at 12 months after HSC transplantation （P〈0.05 compared with pre-transplantation level）. There were no significant differences in ALT, total bilirubin and prothromhin time between the two groups either before or after transplantation. Moreover, Knodell score decreased significantly at 6 and 12 months. Histological examination showed that liver cell edema, degeneration, necrosis, and inflammation were significantly relieved at 3, 6, and 12 months after transplantation. The incidence of portal vein thrombosis, upper gastrointestinal bleeding, and hepatic encephalopathy were 1.25%, 3.75%, and 2.5% respectively. The one-year survival rate was 100%. Conclusions Autologous HSC transplantation improves liver function and histology in ESLD patients The administration route of HSC has no significant impact on the efficacy of transplantation.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418101)the State Key Laboratory of Freshwater Ecology and Biotechnology (No. 2008FBZ01)
文摘We used aerated systems to assess the influence of the bacterioplankton community on cyanobacterial blooms in algae/post-bloom of Lake Taihu, China. Bacterioplankton community diversity was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） fingerprinting. Chemical analysis and nitrogen dynamic changes illustrated that NH4＋-N was nitrified to NO2^--N and NO3^--N by bacterioplankton. Finally, NHa^＋-N was exhausted and NO3^--N was denitrified to NO2^--N, while the accumulation of NO2^--N indicated that bacterioplankton with completely aerobic denitrification ability were lacking in the water samples collected from Lake Taihu. We suggested that adding completely aerobic denitrification bacteria （to denitrify NO2^--N to N2） would improve the water quality. PCR-DGGE and sequencing results showed that more than 1/3 of the bacterial species were associated with the removal of nitrogen, and Acidovorax temperans was the dominant one. PCR-DGGE, variation of nitrogen, removal efficiencies of chlorophyll-a and canonical correspondence analysis indicated that the bacterioplankton significantly influenced the physiological and biochemical changes of cyanobacteria. Additionally, the unweighted pair-group method with arithmetic means revealed there was no obvious harm to the microecosystem from aeration. The present study demonstrated that bacterioplankton can play crucial roles in aerated ecosystems, which could control the impact of cyanobacterial blooms in eutrophicated fresh water systems.
基金the National Natural Science Foundation of China(No.81870669No.81900875)+1 种基金Jiangsu Provincial Natural Science(No.BK20191059)Jiangsu Provincial Commission of Health and Family Planning(No.H201608)。
文摘AIM:To explore retinal displacement after surgical treatment for idiopathic macular hole(IMH)with different internal limiting membrane(ILM)peeling patterns.METHODS:Totally 22 eyes from 20 patients with IMH were randomly allocated into two groups,N-T group(11 eyes)and T-N group(11 eyes).For patients in N-T group,ILM was peeled off from nasal to temporal retina.For patients in T-N group,ILM was peeled off from temporal to nasal retina.Preoperative,postoperative 1,3,and 6 mo,autofluorescence fundus images were collected for manual measurement of distances of fixed nasal(N),temporal(T),superior(S),and inferior(I)retinal points(bifurcation or crossing of retinal vessels)around the macula to the optic disc(OD).These were respectively defined as N-OD,T-OD,S-OD,and I-OD.The retinal displacement,macular holeclosure rate,and best corrected visual acuity(BCVA)were compared between the two groups after surgery.RESULTS:At postoperative 1,3,and 6 mo,the macula slipped toward the OD,manifested by the decreased T-OD,N-OD,S-OD,and I-OD(P<0.05).No significant difference was found in the T-OD,N-OD,S-OD,and I-OD between N-T group and T-N group.IMH closure rate was 100%both in N-T group and T-N group.There was no significant difference in BCVA between two groups(P<0.05).CONCLUSION:The macula slips toward the OD after successful macular hole surgery.The two different ILM peeling pattern show similar visual outcome and retinal displacement,which means ILM peeling directions are not the influencing factor of postoperative retinal displacement.
基金This program was supported by National Key Basic Research Program(973)(No.G1998051125).
文摘A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by 1H-NMR and MS.
基金supported by the National Natural Science Foundation of China(Nos.21801200 and 22075217)the Open Project of Hunan Key Laboratory of Applied Environmental Photocatalysis(No.2114504)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘Sodium-ion batteries are promising candidates for large-scale grid storage systems and other applications.Their foremost advantage derives from superior environmental credentials,enhanced safety as well as lower raw material costs than lithium-ion batteries.It is still challenging to explore desirable anode material.In this study,FeSe_(2)@CoSe_(2)/FeSe_(2),with a yolk-shell structure was prepared by ion exchange and selenisation.The FeSe_(2)@CoSe_(2)/FeSe_(2)prepared as anode material for sodiumion batteries exhibits excellent rate capability due to the synergistic effect of bimetallic selenides and the interfacial effect of the heterostructure.Moreover,it delivers high performance(510 mAh g^(-1)at 0.2 A g^(-1)),superior rate capa-bility(90%retention at 5 A g^(-1)),and good long-time cycling stability(78%capacity retention after 1800 cycles at a high current density of 2 A g^(-1)).The optimized sodiumion full cell with FeSe_(2)@CoSe_(2)/FeSe_(2)as the anode and Na 3 V 2(PO 4)3 as the cathode still demonstrates excellent performance.Namely,a ca-pacity of 272 mAh g^(-1)(at 1 A g^(-1))within the operating voltage from 1 to 3.8 V can be obtained.This work illustrates the potential of bimetallic selenides with heterostructures for performance enhancement of sodium-ion batteries.
基金supported by the National Water Pollution Control and Management Technology Major Project(No.2012ZX07101-010)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2011FBZ07)
文摘The effect of cyanobacterial bloom decay on water quality and the complete degradation of cyanobacterial blooms in a short period were examined by an enclosure experiment in Gonghu Bay of Lake Taihu,China.Water quality parameters as well as taste and odor compounds during the breakdown of cyanobacterial blooms were measured.Results showed that the decay of cyanobacterial blooms caused anoxic water conditions,decreased pH,and increased nutrient loading to the lake water.The highest concentrations of dimethyl sulfide （DMS）,dimethyl trisulfide （DMTS）,and β-cyclocitral were observed in the anoxic water,at 62331.8,12413.3,and 1374.9 ng/L,respectively.2-Methylisoborneol was dominant during the live growth phase of cyanobacterial blooms,whereas DMS and DMTS were dominant during the decomposition phase.Dissolved oxygen,pH,and chlorophyll a were negatively correlated with DMS,DMTS,and β-cyclocitral,whereas total phosphorus,total nitrogen,and ammonium （NH4＋-N） were positively correlated with DMS,DMTS,β-cyclocitral,and β-ionone.The experimental results suggested that preventing the anaerobic decomposition of cyanobacterial blooms is an important strategy against the recurrence of a malodor crisis in Lake Taihu.
基金supported in part by National Key Research and Development Program of China(2019YFB2103200)NSFC(61672108),Open Subject Funds of Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory(SKX182010049)+1 种基金the Fundamental Research Funds for the Central Universities(5004193192019PTB-019)the Industrial Internet Innovation and Development Project 2018 of China.
文摘The development of cloud computing and virtualization technology has brought great challenges to the reliability of data center services.Data centers typically contain a large number of compute and storage nodes which may fail and affect the quality of service.Failure prediction is an important means of ensuring service availability.Predicting node failure in cloud-based data centers is challenging because the failure symptoms reflected have complex characteristics,and the distribution imbalance between the failure sample and the normal sample is widespread,resulting in inaccurate failure prediction.Targeting these challenges,this paper proposes a novel failure prediction method FP-STE(Failure Prediction based on Spatio-temporal Feature Extraction).Firstly,an improved recurrent neural network HW-GRU(Improved GRU based on HighWay network)and a convolutional neural network CNN are used to extract the temporal features and spatial features of multivariate data respectively to increase the discrimination of different types of failure symptoms which improves the accuracy of prediction.Then the intermediate results of the two models are added as features into SCSXGBoost to predict the possibility and the precise type of node failure in the future.SCS-XGBoost is an ensemble learning model that is improved by the integrated strategy of oversampling and cost-sensitive learning.Experimental results based on real data sets confirm the effectiveness and superiority of FP-STE.
基金Supported by National Basic Research Program of China (973 Program, No.2013CB967503)General Project of the National Natural Science Fund (No.81170855)
文摘AIM： To estimate the effectiveness of phacoemulsification and foldable intraocular lens（IOL） implantation combined with transpupillary silicone oil removal.METHODS： There were 168 eyes of 168 candidate patients with cataract and silicone oil-filled eyes recruited in our study. All of the patients received the intraocular silicone oil removal surgery by transpupillary drainage and cataract extraction by phacoemulsification. Then the IOL implantation were also performed through corneal incision. RESULTS： The surgery was successfully completed in all eyes. Best corrected visual acuity（BCVA） and postoperative complications were recorded in three months after surgery. There were 143 eyes with BCVA improved, otherwise 25 eyes remained stable at the last follow-up visit. The mean BCVA statistically improved from 20/400±0.02 to 20/100±0.15（P〈0.001） and mean postoperative IOP was 13.85±2.18 mm Hg（P=0.415）. No intra-operative complications were reported.CONCLUSION： Phacoemulsification combined with transpupillary removal of silicone oil is a safe and simple effective method. In general, it enables quick recovery of visual acuity with less complication rate.
文摘Ultraviolet（UV） radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization＇s measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418101)the State Key Laboratory of Freshwater Ecology and Biotechnology (No. 2008FBZ01)
文摘We conducted an experiment to study the interaction effects of Microcystis aeruginosa and Pseudomonas pseudoalcaligenes on off-flavors in an algae/bacteria co-culture system at three temperatures（24, 28 and 32℃）. Gas chromatography-mass spectrometry was applied to measure off-flavor compounds dimethyl sulfide（DMS）, dimethyl trisulfide（DMTS）,2-methylisoborneol, geosmin（GEO） and β-cyclocitral. During the lag phase of co-cultured M. aeruginosa（first 15 days）, P. pseudoalcaligenes significantly increased the production of DMS, DMTS and β-cyclocitral at all three temperatures. In the exponential phase of co-cultured M. aeruginosa（after 15 days）, M. aeruginosa became the main factor on off-flavors in the co-culture system, and β-cyclocitral turned to the highest off-flavor compound. These results also indicated that DMS, DMTS and β-cyclocitral were the main off-flavor compounds in our M. aeruginosa/P. pseudoalcaligenes co-culture system. Univariate analysis was applied to investigate the effects of M. aeruginosa and P. pseudoalcaligenes on the production of off-flavors. The results demonstrated that both M. aeruginosa and P. pseudoalcaligenes could increase the production of DMS and DMTS, while β-cyclocitral was mainly determined by M. aeruginosa. Our results also provide some insights into understanding the relationship between cyanobacteria and heterotrophic bacteria.
