Molecular level dynamics of genetic oscillator--the effect of protein-protein interaction

Uncovering how interactions of a set of molecular components influence the system's dynamic behavior is important for understanding intracellular processes and elucidating design principles, but unfortunately, there are limited efforts for studying this issue. Here, we study the effect of distinct post-translational dynamics controlled by protein dimerization on oscillations in the repressilator. For this, we propose three biologically motivated model scenarios of the repressilator with monomer or dimer being the active form of repressor, and with protein-protein interactions. It is found that the dimer dissociation constant can tune oscillatory regions, frequency and amplitude. Introducing a modified linear noise approximation to evaluate fluctuations of amplitude and period in the oscillatory systems, we show that different dimerization leads to a different effect on period and amplitude in reducing noise. The manipulation of the circuit's biochemical properties provides a practical strategy for designing a robust and tunable oscillator.

Indications of suppression of excited Υ states in Pb-Pb collisions at √(s(NN))=2.76 TeV

A comparison of the relative yields of Υ resonances in the μ(+)μ(-) decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76 TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4  GeV/c and pseudorapidity below 2.4, the double ratio of the Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)](Pb-Pb)/[Υ(2S+3S)/Υ(1S)](pp), is found to be 0.31(-0.15)(+0.19)(stat)±0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%.

In vitro myometrial contractility reflects indication for caesarean section

OBJECTIVE

To assess the extent to which in vitro measurements of myometrial contractility reflect the clinical indication for caesarean section.

DESIGN

A prospective, observational hypothesis-generating study.

SETTING

Women were recruited from Liverpool Women's NHS Foundation Trust and experiments were performed in the Physiology Department at the University of Liverpool.

POPULATION

Myometrial samples were taken from women undergoing a caesarean section during labour (n = 50) or from women having a repeat nonlabouring caesarean section (n = 70).

METHODS

The demographic characteristics of the women and indications for current and previous caesarean sections were recorded. The force, frequency and duration of spontaneous contractions of myometrial strips, and changes in the intracellular calcium concentration of the strips, were measured. Kruskall-Wallis and post hoc tests were used to assess the significance of differences between groups.

RESULTS

Samples from women whose caesarean section was for fetal distress/acidosis (scalp pH <7.2) contracted with more force than those from women whose caesarean section was for delay in the first stage of labour (P < 0.001). For repeat, nonlabouring caesarean sections, samples from women whose first caesarean section was for fetal distress/acidosis also contracted with more force than did samples from women whose first caesarean section was for delay in the first stage of labour (P = 0.03).

CONCLUSIONS

These findings suggest that the myometrium contracts with greater force in women who have a caesarean section for fetal distress.

Developments of combretastatin A-4 derivatives as anticancer agents

Tubulin protein is one of several members of a small family of globular proteins. It offers a potential target for anticancer drug design and development. Combretastatin A-4 (CA-4) is a potent anticancer and antiangiogenesis natural substance isolated from Combretum caffrum. Modifications on the CA-4 structure have led to a great number of novel CA-4 derivatives as potent tubulin inhibitors and high cytotoxic anticancer agents is becoming an interesting field, leading to a breakthrough in the treatment of cancer. In this review, the recent developments of novel CA-4 derivatives via the modifications on the A- and B-ring and the double bond as anticancer agents are discussed.

High cell density and productivity culture of Chinese hamster ovary cells in a fluidized bed bioreactor

A recombinant Chinese hamster ovary clone was cultivated in a 2L Cytopilot Mini fluidized bed bioreactor using Cytoline 1 microcarriers and a 10L B. Braun stirred tank bioreactor with Cytodex 1 microcarriers. Cytoline 1 is a macroporous polyethylene microcarrier and Cytodex 1 is a solid DEAE-dextran microcarrier. Cytoline 1 microcarriers in the fluidized bed bioreactor were gently mixed by an uplifting flow. Circulation and sparging in Cytopilot Mini were separated from the fluidized microcarrier bed. Cytopilot Mini bioreactor with Cytoline 1 microcarriers offered 2.3 times more surface area than the stirred tank bioreactor. The 2L fluidized bed bioreactor accommodated approximately half the cells in the 10L stirred tank bioreactor. Moreover, Cytopilot Mini had approximately three times more product output rate and 5.5 times higher specific productivity than the stirred tank bioreactor.

Serological survey of antibodies to influenza A viruses in a group of people without a history of influenza vaccination

A serological survey for antibodies to influenza viruses was performed in China on a group of people without a history of influenza vaccination. Using the haemagglutination inhibition (HI) assay, we found seropositivity rates for seasonal H3N2 to be significantly higher than those for seasonal H1N1. Samples positive for antibodies to the pandemic (H1N1) 2009 virus increased from 0.6% pre-outbreak to 4.5% (p <0.01) at 1 year post-outbreak. Interestingly, HI and neutralization tests showed that 1.4% of people in the group have antibodies recognizing H9N2 avian influenza viruses, suggesting that infection with this subtype may be more common than previously thought.

Measurement of the polarization of W bosons with large transverse momenta in W + jets events at the LHC

A first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb⁻¹ of data recorded at √s = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (f(L), f(R), and f₀, respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final state yields the most precise measurement: (f(L) - f(R))⁻ = 0.240 ± 0.036(stat) ± 0.031(syst) and f₀⁻ = 0.183 ± 0.087(stat) ± 0.123(syst) for negatively charged W bosons and (f(L) - f(R))⁺ = 0.310 ± 0.036(stat) ± 0.017(syst) and f₀⁺ = 0.171 ± 0.085(stat) ± 0.099(syst) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model.

Icarisid II, a PDE5 inhibitor from Epimedium wanshanense, increases cellular cGMP by enhancing NOS in diabetic ED rats corpus cavernosum tissue

The aim of this study was to explore the effects and mechanisms of Icarisid II (ICA-II) on enhancing the cellular cGMP in rat corpus cavernosum tissue (RCCT). Diabetes mellitus Wistar rats were induced by streptozotocin, and diabetic ED rats were selected for the RCCT culture by apomorphine. ICA-II was extracted and purified from Icariin (ICA) by enzymatic method. The RCCT was treated with ICA-II, ICA and Sildenafil at different concentrations. cGMP and nitric oxide synthase (NOS) activities were checked respectively by enzyme immunoassay. Meanwhile, nNOS, iNOS and eNOS in RCCT were checked by western blot. ICA-II evaluated the intracellular cGMP to 8.01 ± 1.02 pmol mg(-1) min(-1), which is much weaker than that from Sildenafil (12.4 ± 1.16 pmol mg(-1) min(-1)) (P < 0.05). There is no significant difference between ICA-II and ICA. With the treatment of 10 μm ICA-II for 24 and 48 h, nNOS expression was significantly increased in RCCT (P < 0.05), while the eNOS expression level was very low without any change. Notably, ICA-II increased the intracellular NOS activity significantly in vitro in RCCT. Except the PDE5 inhibitory effect, ICA-II increases the intracellular cGMP through the enhancement of nNOS expression and NOS activity in RCCT in vitro. ICA-II implies a potential compound for neurogenic erectile dysfunction by NO-cGMP pathway.

Control of postharvest Botrytis fruit rot of strawberry by volatile organic compounds of Candida intermedia

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P < 0.01) reduced by exposure of the strawberry fruit to the volatiles from C. intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.

Does the individualized reference outperform a simple ultrasound-based reference applied to birth weight in predicting child neurodevelopment?

OBJECTIVES

Being small-for-gestational age (SGA) is associated with an increased risk of morbidity, but questions remain about how best to diagnose SGA, and thus, predict poor health consequences. The authors sought to compare an individualized reference for defining SGA with simple birth weight-based and ultrasound-based references applied to birth weight in predicting poor cognitive development at age five.

METHODS

The authors used data from the Successive SGA Births Study, a prospective study including 699 Alabaman and 618 Scandinavian women recruited from 1986 to 1988, and whose children had cognitive development scores measured at age five using the Wechsler Preschool and Primary Scale of Intelligence-Revised Intelligence Quotient. Sensitivity, specificity and positive predictive value (PPV) were estimated for each reference applied to birth weight using adverse cognitive development (score < 10(th) percentile) as the outcome. Relative risk of poor neurodevelopment was calculated, comparing infants classified as SGA by either the individualized or the simple ultrasound-based reference with infants not classified as SGA.

RESULTS

The individualized reference had higher specificity and PPV in predicting poor neurodevelopment. Neonates defined as SGA by the individualized reference alone had a higher risk (RR=2.20, 95% CI: 1.20, 4.00) of poor cognitive outcome, while those identified by the ultrasound-based reference alone did not (RR=0.95, 95% CI: 0.45, 2.01). None of the references could predict poor neurodevelopment well at age five.

CONCLUSIONS

The individualized birth weight reference modestly outperforms the simple ultrasound-based reference in identifying SGA infants with poor child neurodevelopment. However, neither reference can predict child neurodevelopment well.

An in-vacuum diffractometer for resonant elastic soft x-ray scattering

We describe the design, construction, and performance of a 4-circle in-vacuum diffractometer for resonant elastic soft x-ray scattering. The diffractometer, installed on the resonant elastic and inelastic x-ray scattering beamline at the Canadian Light Source, includes 9 in-vacuum motions driven by in-vacuum stepper motors and operates in ultra-high vacuum at base pressure of 2 × 10(-10) Torr. Cooling to a base temperature of 18 K is provided with a closed-cycle cryostat. The diffractometer includes a choice of 3 photon detectors: a photodiode, a channeltron, and a 2D sensitive channelplate detector. Along with variable slit and filter options, these detectors are suitable for studying a wide range of phenomena having both weak and strong diffraction signals. Example measurements of diffraction and reflectivity in Nd-doped (La,Sr)(2)CuO(4) and thin film (Ga,Mn)As are shown.

Quantification of inertial sensor-based 3D joint angle measurement accuracy using an instrumented gimbal

This study quantified the accuracy of inertial sensors in 3D anatomical joint angle measurement with respect to an instrumented gimbal. The gimbal rotated about three axes and directly measured the angles in the ISB recommended knee joint coordinate system. Through the use of sensor attachment devices physically fixed to the gimbal, the joint angle estimation error due to sensor attachment (the inaccuracy of the sensor attachment matrix) was essentially eliminated, leaving only error due to the inertial sensors. The angle estimation error (RMSE) corresponding to the sensor was found to be 3.20° in flexion/extension, 3.42° in abduction/adduction and 2.88° in internal/external rotation. Bland-Altman means of maximum absolute value were -1.63° inflexion/extension, 3.22° in abduction/adduction and -2.61° in internal/external rotation. The magnitude of the errors reported in this study imply that even under ideal conditions irreproducible in human gait studies, inertial angle measurement will be subject to errors of a few degrees. Conversely, the reported errors are smaller than those reported previously in human gait studies, which suggest that the sensor attachment is also significant source of error in inertial gait measurement. The proposed apparatus and methodology could be used to quantify the performance of different sensor systems and orientation estimation algorithms, and to verify experimental protocols before human experimentation.

Measurement of the B0 production cross section in pp collisions at sqrt[s] = 7 TeV

Measurements of the differential production cross sections dσ/dpTB and dσ/dyB for B0 mesons produced in pp collisions at sqrt[s] = 7 TeV are presented. The data set used was collected by the CMS experiment at the LHC and corresponds to an integrated luminosity of 40 pb-1. The production cross section is measured from B0 meson decays reconstructed in the exclusive final state J/ψKS0, with the subsequent decays J/ψ → μ + μ - and KS0 → π+}π-. The total cross section for pTB>5 GeV and |yB|<2.2 is measured to be 33.2 ± 2.5 ± 3.5 μb, where the first uncertainty is statistical and the second is systematic.

Metabotropic glutamate receptor 5 promotes proliferation of human neural stem/progenitor cells with activation of mitogen-activated protein kinases signaling pathway in vitro

Metabotropic glutamate receptors (mGluRs) regulate neurogenesis in brain, but the mechanisms remain unknown. In this study, we investigated the effect of mGluR5 on the proliferation of human embryonic neural stem/progenitor cells (NPCs), the expression of cyclin D1 and the activation of signaling pathways of mitogen-activated protein kinases (MAPKs). Results showed that mGluR5 agonist (S)-3,5-dihydroxyphenylglycine hydrate (DHPG) increased the proliferation of NPCs by increasing cell activity, diameter of neurospheres and cell division, while mGluR5 siRNA and antagonist 6-methyl-2-(phenylethynyl) pyridine hydrochloride (MPEP) decreased the NPC proliferation. The mRNA and protein expressions of cyclin D1 increased with DHPG treatment and decreased after siRNA or MPEP treatment. It was also found that activation of extracellular signal-regulated protein kinase (ERK) and c-Jun N-terminal protein kinase (JNK) signaling pathways were involved in the proliferation of NPCs. After DHPG treatment, p-ERK1/2 and p-JNK2 levels increased, and meanwhile p-p38 level decreased; but p-ERK1/2 and p-JNK2 levels decreased after siRNA or MPEP treatment, and p-p38 level increased. Our findings demonstrated that mGluR5 promoted the proliferation of human embryonic cortical NPCs and increased cyclin D1 expression with the changes in phosphorylation of MAPKs signaling pathways in vitro, suggesting a novel mechanism for pharmacological study of treatment for ischemic brain injury and neurodegenerative disorders.

Intestinal pseudo-obstruction syndrome in systemic lupus erythematosus

Intestinal pseudo-obstruction (IpsO) occurs in a small subgroup of patients with systemic lupus erythematosus (SLE), and has been under-recognized. The etiology and mechanisms are unclear. Herein, we report two cases. In case 1, IpsO occurred as the complication in a previously diagnosed SLE patient. In case 2, IpsO with an image-evidenced intussusception and a peripheral eosinophilia, was the initial presentation, leading to the diagnosis of SLE. In both cases, IpsO existed concomitantly with ureterohydronephrosis, and evolved into peritonitis, which we called together IpsO syndrome. However, this surgical abdomen-like syndrome had a satisfactory response to glucocorticosteroids instead of antibiotics and surgery. Physician awareness and early diagnosis could positively affect outcomes of this syndrome, avoiding unnecessary surgical intervention.