What do an odd lab-derived strain of influenza, fowl plague virus, and the 1997 Hong Kong chicken flu have in common? The answer lies in how, and more specifically by what protease, the hemagglutinin protein of these various influenza strains is cleaved for viral activation. What does this have to do with the most devastating influenza virus of them all, the 1918 ‘‘Spanish’’ influenza? The conn...

To investigate the aetiology of the 2015 A(H1N1)pdm09 influenza outbreak in India, 1,083 nasopharyngeal swabs from suspect patients were screened for influenza A(H1N1)pdm09 in the state of Madhya Pradesh. Of 412 positive specimens, six were further characterised by phylogenetic analysis of haemagglutinin (HA) sequences revealing that they belonged to genogroup 6B. A new mutation (E164G) was obs...

The haemagglutinin (HA) complex of Clostridium botulinum type C toxin is composed of three types of subcomponents: HA33, HA17 and HA70 (also known as HA1, HA2 and HA3, respectively). Here, a 260 kDa HA17-HA70 complex was crystallized. His-tagged HA17 and maltose-binding-protein-tagged HA70 were expressed in Escherichia coli and their complex was affinity-purified using a combination of amylose ...

The ectodomain of the Ebola virus Gp2 glycoprotein was solubilized with a trimeric, isoleucine zipper derived from GCN4 (pIIGCN4) in place of the hydrophobic fusion peptide at the N terminus. This chimeric molecule forms a trimeric, highly alpha-helical, and very thermostable molecule, as determined by chemical crosslinking and circular dichroism. Electron microscopy indicates that Gp2 folds in...

A snake (of length L) is a (continuous) piecewise C1-curve S : [0, L] → R, parameterized by arc-length and whose “tail” is at the origin (S(0) = 0). Charming a snake consists in having it move in such a way that its “snout” S(L) follows a chosen C1-curve γ(t). The snake charmer algorithm, initiated in [Ha2] for polygonal snakes and developed in [Ro] in the general case, works as follows. The in...

Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical a...

An H4N6 subtype avian influenza virus was isolated from a pockmark duck in southern China in November 2013 and named A/duck/Guangxi/149D24/2013 (H4N6). All eight gene segments of the strain were sequenced. Sequence analysis indicated that this H4N6 virus was a natural reassortant virus. This H4N6 virus has two basic amino acids in the cleavage site of hemagglutinin 1 (HA1) and HA2, and the amin...

This paper describes methods to produce an isotopically labeled 23 kDa viral membrane protein with purified yield of 20 mg/L of Esch­e­rich­ia coli shake flask culture. This yield is suf­fi­cient for NMR structural studies and the protein production methods are simple, straightforward, and rapid and likely applicable to other recombinant membrane proteins expressed in E. coli. The target FHA2 p...