Mechanisms of mouse spleen dendritic cell function in the generation of influenza-specific, cytolytic T lymphocytes

We have evaluated the capacity of dendritic ceUs to function as antigen-presenting cells (APCs) for influenza and have examined their mechanism of action. Virus-pulsed dendritic cells were 100 times more efficent than bulk spleen ceUs in stimulating cytotoxic T lymphocyte (CTL) formation. The induction of CTLs required neither exogenous lymphokines nor APCs in the responding T cell population. Infectious virus entered dendritic cells through intraceUular acidic vacuoles and directed the synthesis of several viral proteins. If ultravidet (UV)-inactivated or bromdain-treated viruses were used, viral protein synthesis could not be detected, and there was poor induction of CTLs. This indicated that dendritic cells were not capable of processing noninfectious virus onto major histocompatibility complex (MHC) class I molecules. However, UV-inactivated and bromdain-treated viruses were presented efficently to class II-restricted CD4+ T ceils. The CD4+ T cells crossreacted with different strains of influenza and markedly amplified CTL formation. Cell lines that lacked MHC class II, and consequently the capacity to stimulate CD4+ T cells, failed to induce CTLs unless hdper lymphokines were added. Similarly, dendritic cells pulsed with the MHC class I-restricted nucleoprotdn 147-155 peptide were poor stimulators in the absence of exogenous hdper factors. We condude that the function of dendritic cells as APCs for the generation of virus-spedfic CTLs in vitro depends measurably upon: (a) charging class I molecules with peptides derived from endogenously synthesized viral antigens, and (b) stimulating a strong CD4+ helper T cell response

Formation of stable homodimer via the C-terminal α-helical domain of coronavirus nonstructural protein 9 is critical for its function in viral replication

AbstractCoronaviruses devote more than three quarters of their coding capacity to encode two large polyproteins (1a and 1ab polyproteins), which are proteolytically processed into 15–16 mature, nonstructural replicase proteins (nsp1 to 16). These cleavage products are believed to play essential roles in replication of the giant RNA genome of ∼30 kb and transcription of a nested set of 5 to 9 subgenomic RNA species by a unique discontinuous transcription mechanism. In this report, one of these replicase proteins, nsp9 of the coronavirus infectious bronchitis virus (IBV) is systematically studied using both biochemical and reverse genetic approaches. The results showed that substitution mutation of a conserved Gly (G98) residue in the C-terminal α-helix domain with an Asp greatly destabilized the IBV nsp9 homodimer and abolished its RNA-binding activity. Introduction of the same mutation into an infectious IBV clone system showed that the mutation totally abolishes the transcription of subgenomic RNA and no infectious virus could be recovered. Mutation of a semi-conserved Ile (I95) residue in the same region showed moderately destabilizing effect on the IBV nsp9 homodimer but minimal effect on its RNA-binding activity. Introduction of the mutation into the IBV infectious clone system showed recovery of a mutant virus with severe growth defects, supporting that dimerization is critical for the function of this replicase protein. Meanwhile, mutations of some positively charged residues in the β-barrel regions of the IBV nsp9 protein significantly reduced its RNA-binding activity, but with no obvious effect on dimerization of the protein. Introduction of these mutations into the viral genome showed only mild to moderate effects on the growth and infectivity of the rescued mutant viruses

Morintides: cargo-free chitin-binding peptides from Moringa oleifera

Statistics of the structure of mO1 generated by CNSsolve 1.3. (DOCX 16 kb

Plasma cholesterol levels and brain development in preterm newborns.

BackgroundTo assess whether postnatal plasma cholesterol levels are associated with microstructural and macrostructural regional brain development in preterm newborns.MethodsSixty preterm newborns (born 24-32 weeks gestational age) were assessed using MRI studies soon after birth and again at term-equivalent age. Blood samples were obtained within 7 days of each MRI scan to analyze for plasma cholesterol and lathosterol (a marker of endogenous cholesterol synthesis) levels. Outcomes were assessed at 3 years using the Bayley Scales of Infant Development, Third Edition.ResultsEarly plasma lathosterol levels were associated with increased axial and radial diffusivities and increased volume of the subcortical white matter. Early plasma cholesterol levels were associated with increased volume of the cerebellum. Early plasma lathosterol levels were associated with a 2-point decrease in motor scores at 3 years.ConclusionsHigher early endogenous cholesterol synthesis is associated with worse microstructural measures and larger volumes in the subcortical white matter that may signify regional edema and worse motor outcomes. Higher early cholesterol is associated with improved cerebellar volumes. Further work is needed to better understand how the balance of cholesterol supply and endogenous synthesis impacts preterm brain development, especially if these may be modifiable factors to improve outcomes

Employing DDBPSK in optical burst switched systems to enhance throughput

We demonstrate that doubly differential decoding can demodulate phase shift keyed data much faster after the switching event of a tunable laser than usual mth power single differential decoding. This technique can significantly improve throughput of optical burst switched networks

Intraoperative Monitoring of the Cochlear Nerve during Neurofibromatosis Type-2 Vestibular Schwannoma Surgery and Description of a "Test Intracochlear Electrode".

Objectives  A decision on whether to insert a cochlear implant can be made in neurofibromatosis 2 (NF2) if there is objective evidence of cochlear nerve (CN) function post vestibular schwannoma (VS) excision. We aimed to develop intraoperative CN monitoring to help in this decision. Design  We describe the intraoperative monitoring of a patient with NF2 and our stimulating and recording set up. A novel test electrode is used to stimulate the CN electrically. Setting  This study was set at a tertiary referral center for skull base pathology. Main outcome measure  Preserved auditory brainstem responses leading to cochlear implantation. Results  Electrical auditory brainstem response (EABR) waveforms will be displayed from different stages of the operation. A cochlear implant was inserted at the same sitting based on the EABR. Conclusion  Electrically evoked CN monitoring can provide objective evidence of CN function after VS excision and aid in the decision-making process of hearing rehabilitation in patients who will be rendered deaf

1,3-Bis(biphenyl-4-yl)-2,2-dibromo-3-oxopropyl acetate

In the title compound, C29H22Br2O3, the dihedral angles between the mean planes of the benzene rings within each biphenyl group are 26.7 (8) and 30.9 (8)°. The mean planes of the terminal and inner benzene rings of the biphenyl groups bonded through a propan-1-one group in the V-shaped mol­ecule are oriented at angles of 66.1 (7) and 60.0 (8)°, respectively. The two Br atoms are opposite the propen-1-one group. Weak inter­molecular C—H⋯O and C—H⋯π inter­actions are observed in the crystal structure

Propulsion in a viscoelastic fluid

Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity U_N, the sheet swims (or transports fluid) with velocity U / U_N = [1+De^2 (eta_s)/(eta) ]/[1+De^2], where eta_s is the viscosity of the Newtonian solvent, eta is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations chosen for the fluid, and are valid for both waves of tangential and normal motion. The generalization to more than one relaxation time is also provided. In stark contrast with the Newtonian case, these calculations suggest that transport and locomotion in a non-Newtonian fluid can be conveniently tuned without having to modify the waving gait of the sheet but instead by passively modulating the material properties of the liquid.Comment: 21 pages, 1 figur

Genetic variants of MICB and PLCE1 and associations with the laboratory features of dengue

Background: A previous genome-wide association study identified 2 susceptibility loci for severe dengue at MICB rs3132468 and PLCE1 rs3740360 and further work showed these mutations to be also associated with less severe clinical presentations. The aim of this study was to determine if these specific loci were associated with laboratory features of dengue that correlate with clinical severity with the aim of elucidating the functional basis of these genetic variants. Methods: This was a case-only analysis of laboratory-confirmed dengue patients obtained from 2 prospective cohort studies and 1 randomised clinical trial in Vietnam (Trial registration: ISRCTN ISRCTN03147572. Registered 24th July 2012). 2742 dengue cases were successfully genotyped at MICB rs3132468 and PLCE1 rs3740360. Laboratory variables were compared between genotypes and stratified by DENV serotype. Results: The analysis showed no association between MICB and PLCE1 genotype and early viraemia level, platelet nadir, white cell count nadir, or maximum haematocrit in both overall analysis and in analysis stratified by serotype. Discussion: The lack of an association between genotype and viremia level may reflect the sampling procedures within the included studies. The study findings mean that the functional basis of these mutations remains unclear. Trial registration: ISRCTN ISRCTN03147572. Registered 24th July 2012