Protein-DNA interactions are essential for gene maintenance, replication and expression. Characterizing how proteins interact with and change the structure of DNA is crucial in elucidating the mechanisms of protein function. Here we present a novel and generalizable method of using engineered DNA Holliday junctions (HJs) that contain specific protein-recognition sequences to report protein-DNA interactions in single-molecule FRET measurements, utilizing the intrinsic structural dynamics of HJs. Since the effects of protein binding are converted to the changes in the structure and dynamics of HJs, protein-DNA interactions that involve small structural changes of DNA can be studied. We apply this method to investigate how the MerR-family regulator PbrR691 interacts with DNA for transcriptional regulation. Both apo- and holo-PbrR691 bind the stacked conformers of the engineered HJ, change their structures, constrain their conformational distributions, alter the kinetics and shift the equilibrium of their structural dynamics. The information obtained maps the potential energy surfaces of HJ before and after PbrR691 binding and reveals the protein actions that force DNA structural changes for transcriptional regulation. The ability of PbrR691 to bind both HJ conformers and still allow HJ structural dynamics also informs about its conformational flexibility that may have significance for its regulatory function. This method of using engineered HJs offers quantification of the changes both in structure and dynamics of DNA upon protein binding and thus provides a new tool to elucidate the correlation of structure, dynamics, and function of DNA-binding proteins.
Tumor necrosis factor-α (TNF-α) 308 G/A gene polymorphism has been reported to be associated with susceptibility to silicosis. However, the relevant study results are still inconsistent.
Objective and Methods
A meta-analysis was performed in order to drive a more precise estimation of the relationship between TNF-α-308 G/A gene polymorphism and susceptibility to silicosis. Electronic databases were searched and nine separate studies were included. The pooled odds ratios (ORs) and the corresponding 95% confidence internal (CI) were calculated by a fixed effect model.
A total of 1267 cases and 1214 controls were included. In the overall analysis, significantly increased silicosis risk was found (for GA+AA vs. GG OR=1.45, 95%CI: 1.20-1.760, P=1.58E4; for GA vs. GG: OR=1.53, 95%CI=1.25-1.86, P=3.11E5; for A allele vs. G allele: OR=1.27, 95%CI=1.08-1.50, P= 0.004). In the subgroup analysis, significantly increased silicosis risk was also found among Asians (for GA+AA vs. GG: OR=1.63, 95%CI=1.27-2.08, P=1.01E4), for GA vs. GG: OR=1.71, 95%CI=1.33-2.20, P=3.44E5), for A allele vs. G allele: OR=1.45, 95%CI=1.17-1.80, P=0.001). However, no significantly increased risk was found among non-Asians for all genetic models.
TNF-α-308 G/A polymorphism might lead to an increased risk of silicosis susceptibility, especially for Asians. However, further studies with large sample sizes should be conducted to confirm the association.
Oil-polluted water is a worldwide problem due to the increasing industrial oily wastewater and the frequent oil spill accidents. Here, we report a novel kind of superhydrophilic hybrid membranes for effective oil/water separation. They were prepared by depositing CaCO3-based mineral coating on PAA-grafted polypropylene microfiltration membranes. The rigid mineral-coating traps abundant water in aqueous environment and forms a robust hydrated layer on the membrane pore surface, thus endowing the membranes with underwater superoleophobicity. Under the drive of either gravity or external pressure, the hybrid membranes separate a range of oil/water mixtures effectively with high water flux (>2000 L m−2 h−1), perfect oil/water separation efficiency (>99%), high oil breakthrough pressure (>140 kPa) and low oil fouling. The oil/water mixtures include not only free mixtures but also oil-in-water emulsions. Therefore, the mineral-coated membrane enables an efficient and energy-saving separation for various oil/water mixtures, showing attractive potential for practical oil/water separation.
Transplantation of stem cells into damaged hearts has had modest success as a treatment for ischemic heart disease. One of the limitations is the poor stem cell survival in the diseased microenvironment. Prolyl hydroxylase domain protein 2 (PHD2) is a cellular oxygen sensor that regulates two key transcription factors involved in cell survival and inflammation, hypoxia-inducible factor (HIF) and nuclear factor-κB (NF-κB).
We studied if and how PHD2 silencing in human adipose-derived stem cells (ADSCs) enhances their cardioprotective effects after transplantation into infarcted hearts.
Methods and Results
ADSCs were transduced with lentiviral shPHD2 to silence PHD2. ADSCs with or without shPHD2 were transplanted after myocardial infarction (MI) in mice. ADSCs reduced cardiomyocyte apoptosis, fibrosis and infarct size and improved cardiac function. shPHD2-ADSCs exerted significantly more protection. PHD2 silencing induced greater ADSCs survival, which was abolished by shHIF-1α. Conditioned medium (CM) from shPHD2-ADSCs decreased cardiomyocyte apoptosis. Insulin-like growth factor 1 (IGF-1) levels were significantly higher in the CM of shPHD2-ADSCs versus ADSCs, and depletion of IGF-1 attenuated the cardioprotective effects of shPHD2-ADSCs-CM. NF-κB activation was induced by shPHD2 to induce IGF-1 secretion via binding to IGF-1 gene promoter.
PHD2 silencing promotes ADSCs survival in MI hearts and enhances their paracrine function to protect cardiomyocytes. The pro-survival effect of shPHD2 on ADSCs is HIF-1α dependent and the enhanced paracrine function of shPHD2-ADSCs is associated with NF-κB-mediated IGF-1 up-regulation. PHD2 silencing in stem cells may be a novel strategy for enhancing the effectiveness of stem cell therapy after MI.
Myocardial infarction; stem cell; survival; paracrine effect; cardiomyocyte
Insects require molting fluids to shed the old cuticle during molting. β-N-acetyl-D-hexosaminidase, known as Hex1, together with various chitinases, is responsible for degrading the chitin component of the old cuticle. This study showed that another β-N-acetyl-D-hexosaminidase, termed OfHex3, interacted with Hex1 and functioned in the molting fluid, although the homolog of OfHex3 was known as a sperm–plasma enzyme functioning in egg–sperm recognition. OfHex3 is an enzyme cloned from the insect Asian corn borer, Ostrinia furnacalis, which is one of the most destructive pests of maize. The enzymatic activity analysis indicated that OfHex3 was able to degrade chitooligosaccharides, but at a lower rate than that of OfHex1. Because OfHex3 did not have substrate inhibition, we deduced that the presence of OfHex3 might help OfHex1 relieve substrate inhibition during chitin degradation during molting. The expression patterns of OfHex3 during O. furnacalis development were studied by real-time PCR as well as western blot. The results showed that both gene transcription and protein translation levels of OfHex3 were up-regulated during larval–larval molting. The tissue-specific expression pattern analysis indicated that OfHex3 was mostly localized in the fat body and testis. All these data further supported that Hex3 was involved in molting as well as in fertilization. This study may help to understand the complexity of cuticle degradation during insect molting, and may provide a possible target for pest control.
atrial fibrillation; Editorials; inflammation; nervous system, autonomic
Specifically, FK506-binding proteins 12 (FKBP12) and 12.6 (FKBP12.6) are cis–trans peptidyl prolyl isomerases that are expressed in the heart. Both FKBP12 and FKBP12.6 were previously known to interact with ryanodine receptors in striated muscles. Although FKBP12 is abundantly present in the heart, its function in the heart is largely uncertain. Recently, by generating FKBP12 transgenic overexpression and cardiac-restricted knockout mice, we showed that FKBP12 is critically important in regulating trans-sarcolemmal ionic currents, predominately the voltage-gated Na+ current, INa, but it appears to be less important for regulating cardiac ryanodine receptor function. Similar genetic approaches also confirm the role of FKBP12.6 in regulating cardiac ryanodine receptors. The current study demonstrated that FKBP12 and FKBP12.6 have very different physiologic functions in the heart.
FK506-binding protein; Cardiac function; Arrhythmia; Voltage-gated sodium channel; Ryanodine receptor; Calcium release
Protein complex of the cardiac junctional sarcoplasmic reticulum (SR) membrane formed by type 2 ryanodine receptor, junction, triadin, and calsequestrin is responsible for controlling SR calcium (Ca) release. Increased intracellular calcium (Cai) activates the electrogenic sodium–Ca exchanger current, which is known to be important in afterdepolarization and triggered activities (TAs). Using optical-mapping techniques, it is possible to simultaneously map membrane potential (Vm) and Cai transient in Langendorff-perfused rabbit ventricles to better define the mechanisms by which Vm and Cai interactions cause early afterdepolarizations (EADs). Phase 3 EAD is dependent on heterogeneously prolonged action potential duration (APD). Electrotonic currents that flow between a persistently depolarized region and its recovered neighbors underlies the mechanisms of phase 3 EADs and TAs. In contrast, “late phase-3 EAD” is induced by APD shortening, not APD prolongation. In failing ventricles, upregulation of apamin-sensitive Ca-activated potassium (K) channels (IKAS) causes APD shortening after fibrillation-defibrillation episodes. Shortened APD in the presence of large Cai transients generates late-phase 3 EADs and recurrent spontaneous ventricular fibrillation. The latter findings suggest that IKAS may be a novel antiarrhythmic targets in patients with heart failure and electrical storms.
Triggered activity; After depolarization; Ventricular fibrillation; Calcium dynamics; Optical mapping
Although the adult mammalian myocardium exhibits a limited ability to undergo regenerative growth, its intrinsic renewal rate is insufficient to compensate for myocyte loss during cardiac disease. Transplantation of donor cardiomyocytes or cardiomyogenic stem cells is considered a promising strategy to reconstitute cardiac mass, provided the engrafted cells functionally integrate with host myocardium and actively contribute to its contractile force. We have previously developed a two-photon fluorescence microscopy-based assay that allows in situ screening of donor cell function following their intracardiac delivery. Here we review the techniques and summarize its application for quantitation of the extent to which a variety of donor cell types stably and functionally couple with the recipient myocardium.
Cellular transplantation; myocardial regeneration; intracellular calcium regulation; two-photon fluorescence microscopy
Apamin sensitive potassium current (IKAS), carried by the type 2 small conductance Ca2+-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles.
To test the hypothesis that amiodarone inhibits IKAS in human embryonic kidney 293 (HEK-293) cells.
We used the patch-clamp technique to study IKAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration.
Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67±0.25 µM with 1 µM intrapipette Ca2+). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of IKAS induced with 1 µM intrapipette Ca2+ (n = 3). IKAS inhibition by amiodarone was not voltage-dependent, but was Ca2+-dependent: 30 µM amiodarone inhibited 81.5±1.9% of IKAS induced with 1 µM Ca2+ (n = 4), and 16.4±4.9% with 250 nM Ca2+ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca2+ dependent inhibition of IKAS.
Both amiodarone and desethylamiodarone inhibit IKAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca2+ concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles.
Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis - abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD20). The adult male survivors from larvae treated with BtA exhibited a higher percentage of “orientation” than control males but lower percentages of “approaching” and “landing” in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11–16:Ald) and Z-9-hexadecenal (Z9–16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11–16:Ald and Z9–16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H.armigera moths that may contribute to assortative mating.
Na channel blockers are effective in suppressing delayed afterdepolarizations (DADs) in isolated Purkinje fibers. However, in isolated mouse ventricular myocytes lacking calsequestrin, only those Na channel blockers that also inhibit type 2 ryanodine receptor channels were effective against spontaneous Ca elevation (SCaE) and DADs.
To test the hypothesis that combined Na channel and type 2 ryanodine receptor channel blocker ((R)-propafenone) is more effective than a Na channel blocker (lidocaine) in suppressing SCaE and DADs in the intact rabbit ventricles.
We compared (R)-propafenone (3 μmol/L) with lidocaine (50 μmol/L) on SCaE and DADs by using epicardial optical mapping of intracellular calcium (Cai) and membrane voltage in Langendorff-perfused rabbit hearts. SCaE and DADs were induced by rapid pacing trains and isoproterenol (0.3 μmol/L) infusion. One arbitrary unit is equivalent to the Ca transient amplitude of paced beats.
SCaEs were observed at the cessation of rapid pacing in all hearts at baseline. (R)-Propafenone nearly completely inhibited DADs and SCaE (0.04 arbitrary units [95% confidence interval 0.02–0.06] vs 0.23 arbitrary units [95% confidence interval 0.18–0.28] at baseline; n = 6 hearts; P < .001). Lidocaine also significantly reduced the SCaE but was significantly (P < .05) less effective than (R)-propafenone. Both drugs increased the rise time of action potential upstroke and reduced conduction velocity to a similar extent, suggesting a significant inhibition of INa.
Both Na channel blockers significantly reduced tachycardia-induced SCaEs in the rabbit ventricles, but (R)-propafenone was significantly more effective than lidocaine. These data suggest that type 2 ryanodine receptor inhibition potentiates the activity of Na channel blockers against SCaE and DADs in the intact hearts.
Depolarization; Action potentials; Calcium; Antiarrhythmic agents
Although a number of leucine-rich repeat receptor-like kinase-encoding genes (LRR-RLKs) have been identified in plants, a functional role has been determined for only a few. Recent studies have demonstrated that an LRR-RLK, PXY/TDR, is important for the process of secondary vascular development. Other studies have indicated that PXY/TDR is unlikely to be the sole LRR-RLK involved in this complex process.
In this study, in silico analyses led to the identification of three Arabidopsis LRR-RLK genes (PXY-correlated; PXC1, 2, 3) with transcript accumulation profiles that correlated strongly with several key regulators of vascular development, including PXY/TDR, HB-8, REV, and CLE41. Expression profiling using qPCR and promoter:reporter lines indicated that all three PXC genes are associated with the vasculature. One in particular, PXC1 (At2g36570), had a strong correlation with PXY/TDR. Shifting pxc1 mutants from long-days to short-days showed that loss of the gene led to a dramatic reduction in secondary wall formation in xylem fibers. Transcript analysis of mutants for a variety of secondary cell wall-associated genes, including PXY/TDR indicated that the pathways mediated by PXC1 connect with those mediated by the TDIF-PXY/TDR-WOX4 system.
The data indicate that the LRR-RLK, PXC1 is involved in secondary cell wall formation in xylem fibers. Whereas further study is needed to identify the ligands and mode of action of the PXC1 protein, it is clear from this work that similarly to the shoot apical meristem (SAM), secondary vascular development requires contributions from a number of LRR-RLKs.
LRR-RLK; Arabidopsis; Secondary Wall Formation; TDIF-PXY/TDR-WOX4 Signaling
We hypothesize that inferior vena cava-inferior atrial ganglionated plexus nerve activity (IVC-IAGPNA) is responsible for the ventricular rate (VR) control during atrial fibrillation (AF) in ambulatory dogs.
Methods and Results
We recorded bilateral cervical vagal nerve activity (VNA) and IVC-IAGPNA during baseline sinus rhythm and during pacing-induced sustained AF in 6 ambulatory dogs. Integrated nerve activities and average VR were measured every 10-s over 24-hour periods. LVNA was associated with VR reduction during AF in 5 dogs (from 211 bpm, 95% confidence interval [CI], 186 to 233 to 178 bpm [95% CI, 145 to 210], p<0.001) and RVNA in 1 dog (208 bpm [95% CI, 197 to 223] to 181 bpm [95% CI, 163 to 200], p<0.01). There were good correlations between IVC-IAGPNA and LVNA in the former 5 dogs, and between IVC-IAGPNA and RVNA in the latter dog. IVC-IAGPNA was associated with VR reduction in all dogs studied. RVNA was associated with baseline sinus rate reduction from 105 bpm (95% CI, 95 to 116) to 77 bpm (95% CI, 64 to 91, p<0.01) in 4 dogs while LVNA was associated with sinus rate reduction from 111 bpm (95% CI, 90 to 1250) to 81 bpm (95% CI, 67 to 103, p<0.01) in 2 dogs.
IVC-IAGPNA is invariably associated with VR reduction during AF. In comparison, right or left VNA was associated with VR reduction only when it co-activates with the IVC-IAGPNA. The vagus nerve that controls VR during AF may be different than that controls sinus rhythm.
atrial fibrillation; atrioventricular node; ECG; nervous system, autonomic; ventricular rate
Enterovirus 80 (EV80) is a newly identified serotype of the species Human enterovirus B. An EV80 strain designated HZ01/SD/CHN/2004 was isolated from an acute flaccid paralysis case in Shandong, China, in 2004. Complete genome comparison revealed 79.5% similarity with the prototype strain and an insertion of 36 nucleotides in the 3′ end of the VP1 coding region. Intertypic recombination with other serotypes was observed. This is the first report of the complete genome of EV80 in China.
A novel intelligent fault diagnosis method for motor roller bearings which operate under unsteady rotating speed and load is proposed in this paper. The pseudo Wigner-Ville distribution (PWVD) and the relative crossing information (RCI) methods are used for extracting the feature spectra from the non-stationary vibration signal measured for condition diagnosis. The RCI is used to automatically extract the feature spectrum from the time-frequency distribution of the vibration signal. The extracted feature spectrum is instantaneous, and not correlated with the rotation speed and load. By using the ant colony optimization (ACO) clustering algorithm, the synthesizing symptom parameters (SSP) for condition diagnosis are obtained. The experimental results shows that the diagnostic sensitivity of the SSP is higher than original symptom parameter (SP), and the SSP can sensitively reflect the characteristics of the feature spectrum for precise condition diagnosis. Finally, a fuzzy diagnosis method based on sequential inference and possibility theory is also proposed, by which the conditions of the machine can be identified sequentially as well.
condition diagnosis; relative crossing information (RCI); pseudo Wigner-Ville distribution (PWVD); ant colony optimization (ACO); synthesizing symptom parameter (SSP)
It has been shown that eNOS uncoupling occurs in hypertension and atherosclerosis. However its causal role in vascular pathogenesis has not been previously characterized. Here, we challenged eNOS pre-uncoupled hph-1 mice (deficient in eNOS cofactor tetrahydrobiopterin biosynthetic enzyme GTPCHI) with Ang II (0.7 mg/kg/day, 14 days). Both wild-type (WT) and hph-1 groups developed hypertension similarly up to day 6 to 7. Thereafter approximately 14% of Ang II-infused (0.7 mg/kg/day) hph-1 mice (n=72) started to die suddenly of ruptured AAA. Among the survivors, 65% developed AAA, resulting in a total morbidity rate of 79%. In contrast, none of the Ang II-infused WT mice died or developed AAA. Ang II progressively deteriorated eNOS uncoupling in hph-1 mice, while augmenting H4B and nitric oxide (NO•) deficiencies. The abundance of the H4B salvage enzyme dihydrofolate reductase (DHFR) in the endothelium was decreased in hph-1 mice and further diminished by Ang II infusion. Intriguingly, restoration of DHFR expression by oral administration of folic acid (FA), or overexpression of DHFR, completely prevented AAA formation in Ang II-infused hph-1 mice while attenuating progressive uncoupling of eNOS. Folic acid also attenuated vascular remodelling and inflammation characterized by medial elastin break down, augmented MMP2 activity and activation of MMP9, as well as macrophage infiltration. In conclusion, these data innovatively suggest a causal role of eNOS uncoupling/H4B deficiency in AAA formation. Therefore oral FA administration, endothelium targeted DHFR gene therapy, and perhaps other countermeasures directed against eNOS uncoupling, could be used as new therapeutics for AAA.
abdominal aortic aneurysm (AAA); eNOS uncoupling; hph-1 mice; tetrahydrobiopterin (H4B); angiotensin II; folic acid (FA); dihydrofolate reductase (DHFR)
As part of intracellular copper trafficking pathways, the human copper chaperone Hah1 delivers Cu+ to the Wilson’s Disease Protein (WDP) via weak and dynamic protein–protein interactions. WDP contains six homologous metal binding domains (MBDs) connected by flexible linkers, and these MBDs all can receive Cu+ from Hah1. The functional roles of the MBD multiplicity in Cu+ trafficking are not well understood. Building on our previous study of the dynamic interactions between Hah1 and the isolated 4th MBD of WDP, here we study how Hah1 interacts with MBD34, a double-domain WDP construct, using single-molecule fluorescence resonance energy transfer (smFRET) combined with vesicle trapping. By alternating the positions of the smFRET donor and acceptor, we systematically probed Hah1–MBD3, Hah1–MBD4, and MBD3–MBD4 interaction dynamics within the multi-domain system. We found that the two interconverting interaction geometries were conserved in both intermolecular Hah1–MBD and intramolecular MBD–MBD interactions. The Hah1–MBD interactions within MBD34 are stabilized by an order of magnitude relative to the isolated single-MBDs, and thermodynamic and kinetic evidences suggest that Hah1 can interact with both MBDs simultaneously. The enhanced interaction stability of Hah1 with the multi-MBD system, the dynamic intramolecular MBD–MBD interactions, and the ability of Hah1 to interact with multiple MBDs simultaneously suggest an efficient and versatile mechanism for the Hah1-to-WDP pathway to transport Cu+.
Plant photosynthesis and photosystem II (PSII) are susceptible to high temperature. However, photosynthetic electron transport process under heat stress remains unclear. To reveal this issue, chlorophyll a fluorescence and modulated 820 nm reflection were simultaneously detected in sweet sorghum. At 43°C, J step in the chlorophyll a fluorescence transient was significantly elevated, suggesting that electron transport beyond primary quinone of PSII (QA) (primary quinone electron acceptor of PSII) was inhibited. PSI (Photosystem I) photochemical capacity was not influenced even under severe heat stress at 48°C. Thus, PSI oxidation was prolonged and PSI re-reduction did not reach normal level. The inhibition of electron transport between PSII and PSI can reduce the possibility of PSI photoinhibition under heat stress. PSII function recovered entirely one day after heat stress at 43°C, implying that sweet sorghum has certain self-remediation capacity. When the temperature reached 48°C, the maximum quantum yield for primary photochemistry and the electron transport from PSII donor side were remarkably decreased, which greatly limited the electron flow to PSI, and PSI re-reduction suspended. The efficiency of an electron transferred from the intersystem electron carrier (plastoquinol, PQH2) to the end electron acceptors at the PSI acceptor side increased significantly at 48°C, and the reason was the greater inhibition of electron transport before PQH2. Thus, the fragment from QA to PQH2 is the most heat sensitive in the electron transport chain between PSII and PSI in sweet sorghum.
We describe a computational analysis method to evaluate the efficacy of immunomagnetic rare cell separation from non-Newtonian particulate blood flow. The core procedure proposed here is calculation of local viscosity distributions induced by red blood cell (RBC) sedimentation. Numerical calculation methods have previously been introduced to simulate particulate behavior of individual RBCs. However, due to the limitation of the computational power, those studies are typically capable of calculating only very small number (less than 100) of RBCs, and are not suitable to analyze many of practical separation methods for rare cells such as circulating tumor cells (CTCs). We introduce a sedimentation and viscosity model based on our experimental measurements. The computational field is divided into small unit control volumes, where local viscosity distribution is dynamically calculated based on the experimentally found sedimentation model. For the analysis of rare cell separation, local viscosity distribution is calculated as a function of the volume RBC rate. The direction of gravity takes an important role in such a sedimentation-involved cell separation system. We evaluated the separation efficacy with multiple design parameters including the channel design, channel operational orientations (inverted and upright) and flow rates. The results showed excellent agreements with real experiments to demonstrate the effectiveness of our computational analytical method. We demonstrated higher capture efficiency with the inverted microchannel configuration. We conclude that proper direction of blood sedimentation significantly enhances separation efficiency in microfluidic devices.
Ion mobility-mass spectrometry (IMMS), an analytical technique which combines the features of ion mobility spectrometry (IMS) and mass spectrometry (MS), can rapidly separates ions on a millisecond time-scale. IMMS becomes a powerful tool to analyzing complex mixtures, especially for the analysis of peptides in proteomics. The high-throughput nature of this technique provides a challenge for the identification of peptides in complex biological samples. As an important parameter, peptide drift time can be used for enhancing downstream data analysis in IMMS-based proteomics.
In this paper, a model is presented based on least square support vectors regression (LS-SVR) method to predict peptide ion drift time in IMMS from the sequence-based features of peptide. Four descriptors were extracted from peptide sequence to represent peptide ions by a 34-component vector. The parameters of LS-SVR were selected by a grid searching strategy, and a 10-fold cross-validation approach was employed for the model training and testing. Our proposed method was tested on three datasets with different charge states. The high prediction performance achieve demonstrate the effectiveness and efficiency of the prediction model.
Our proposed LS-SVR model can predict peptide drift time from sequence information in relative high prediction accuracy by a test on a dataset of 595 peptides. This work can enhance the confidence of protein identification by combining with current protein searching techniques.
Grafting desirable scion on stress-tolerant rootstocks provides an opportunity to improve the cryotolerance of scion. Genic male sterile (GMS) lines of plant could be used as sterile line and maintainer in breeding, and they have the conspicuous characteristics that the fertility of which is easy to regain but hard to maintain by sexual reproduction. In order to maintain the fertility of GMS cotton by means of its perennial growth on the basis of frostless winters in Nanning, Guangxi autonomous region, GMS line A4 was grafted onto 7 cryotolerant rootstocks (F118, F697, F098, F112, F113, P098 and P113), and the cryotolerance and the overwintering survivorship of scions were investigated. In consequence, when compared with control (self-grafted A4), the relative conductivity of the grafted plants in shoot bark was reduced (8.80%), the content of soluble sugar, soluble protein and free proline were higher, 25.00, 1.55, 3.46%, respectively; the overwintering survival rate and the height of regeneration bud under field condition of grafted plants were higher, 10.44, 15.75%, respectively; the order of the grafted plants based on the average subordinate function value of overwintering survivorship was A4/F113>A4/F118>A4/F098>A4/F697>A4/F112>A4/P098>A4/P113>A4/A4(CK); the correlation analyses indicated that the physiological parameters of cryotolerance could be used for forecasting the overwintering survivorship, and the relative conductivity could be chosen as the first physiological parameter for forecasting cryotolerance or overwintering survivorship. The results indicate that the cryotolerance and the overwintering survivorship of GMS cotton could be improved by grafting, and F113 appeared to be a valuable rootstock.
Myocardial infarction (MI) results in cardiac nerve sprouting in the myocardium. Whether or not similar neural remodeling occurs in the stellate ganglia (SG) is unknown. We aimed to test the hypothesis that MI induces bilateral SG nerve sprouting.
Acute MI was created by coronary artery ligation in rabbits (n=12). Serum nerve growth factor (NGF) level was measured by enzyme-linked immunosorbent assay (ELISA). The hearts and bilateral SGs were harvested for immunohistochemistry after 1 week in 6 rabbits, and after 1 month in 6 rabbits. Immunostaining for tyrosine hydroxylase (TH), growth-associated protein 43 (GAP43), cholineacetyltransferase (ChAT) and synaptophysin (SYN) was performed to determine the magnitude of nerve sprouting. Tissues from 6 normal rabbits were used as controls. Nerve density was determined by computerized morphometry.
MI results in increased serum NGF levels at 1 week (1519.8±632.2 ng/ml) that persists to 1 month (1361.2±176.3 ng/ml) as compared to controls (89.6±34.9 ng/ml), (p=.0002, and , p=.0001, respectively). Immunostaining demonstrated nerve sprouting and hyperinnervation in both SGs after MI. The nerve densities (µm2/ganglion cell) in SG 1 week after MI, 1 month after MI and in control groups, respectively, were: GAP43, 278±96, 225±39 and 149±57 (p=.01); SYN, 244±152, 268±115 and 102±60 (p=.02); TH, 233±71, 180±50 and 135±68 (p=.047); ChAT, 244±100, 208±46 and 130±41 µm2/cell (p=.01).
MI increases serum NGF levels and induces nerve sprouting and hyperinnervation in bilateral SGs for at least 1 month after MI. The hyperinnervation includes both postganglionic adrenergic axons and preganglionic cholinergic axons in the SG.
Myocardial Infarction; Ventricular Arrhythmia; Autonomic Nervous System; Stellate Ganglion; Nerve Sprouting; Sudden Cardiac Death
Cell therapy is a novel investigational approach to enhance stroke recovery. Intra-arterial (IA) delivery has the potential advantage of selectively targeting cell therapies to the ischemic brain tissue. Over the past 10 years, IA cell delivery has been under investigation in patients with cardiac and peripheral vascular disease, and these studies have reported promising results. This article reviews the trial methodology and procedural details of these studies and discusses the rationale and challenges in designing IA cell therapy trials for ischemic stroke.