Resonance assignments for latherin,a natural surfactant protein from horse sweat

Latherin is an intrinsically surfactant protein of ~23 kDa found in the sweat and saliva of horses. Its function is probably to enhance the translocation of sweat water from the skin to the surface of the pelt for evaporative cooling. Its role in saliva may be to enhance the wetting, softening and maceration of the dry, fibrous food for which equines are adapted. Latherin is unusual in its relatively high content of aliphatic amino acids (~25 % leucines) that might contribute to its surfactant properties. Latherin is related to the palate, lung, and nasal epithelium carcinoma-associated proteins (PLUNCs) of mammals, at least one of which is now known to exhibit similar surfactant activity to latherin. No structures of any PLUNC protein are currently available. ¹⁵N,¹³C-labelled recombinant latherin was produced in Escherichia coli, and essentially all of the resonances were assigned despite the signal overlap due to the preponderance of leucines. The most notable exceptions include a number of residues located in an apparently dynamic loop region between residues 145 and 154. The assignments have been deposited with BMRB accession number 19067.     

The Effect of Inhibitors on Sulphate Reducing Bacteria: a Compilation

Summary: The effects of about 200 bacteriostatic and bactericidal agents on sulphate reducing bacteria, including some hitherto unpublished results, are tabulated.     

Bidirectional C and N transfer and a potential role for sulfur in an epiphytic diazotrophic mutualism

In nitrogen-limited boreal forests, associations between feathermoss and diazotrophic cyanobacteria control nitrogen inputs and thus carbon cycling, but little is known about the molecular regulators required for initiation and maintenance of these associations. Specifically, a benefit to the cyanobacteria is not known, challenging whether the association is a nutritional mutualism. Targeted mutagenesis of the cyanobacterial alkane sulfonate monooxygenase results in an inability to colonize feathermosses by the cyanobacterium Nostoc punctiforme, suggesting a role for organic sulfur in communication or nutrition. Isotope probing paired with high-resolution imaging mass spectrometry (NanoSIMS) demonstrated bidirectional elemental transfer between partners, with carbon and sulfur both being transferred to the cyanobacteria, and nitrogen transferred to the moss. These results support the hypothesis that moss and cyanobacteria enter a mutualistic exosymbiosis with substantial bidirectional material exchange of carbon and nitrogen and potential signaling through sulfur compounds.Subject terms: Microbial ecology, Plant ecology, Biogeochemistry, Stable isotope analysis     

β-alanine elevates dopamine levels in the rat nucleus accumbens: antagonism by strychnine

Glycine receptors (GlyRs) in the nucleus accumbens (nAc) have recently been suggested to be involved in the reinforcing and dopamine-elevating properties of ethanol via a neuronal circuitry involving the VTA. Apart from ethanol, both glycine and taurine have the ability to modulate dopamine output via GlyRs in the same brain region. In the present study, we wanted to explore whether yet another endogenous ligand for the GlyR, β-alanine, had similar effects. To this end, we monitored dopamine in the nAc by means of in vivo microdialysis and found that local perfusion of β-alanine increased dopamine output. In line with previous observations investigating ethanol, glycine and taurine, the competitive GlyR antagonist strychnine completely blocked the dopamine elevation. The present results suggest that β-alanine has the ability to modulate dopamine levels in the nAc via strychnine-sensitive GlyRs, and are consistent with previous studies suggesting the importance of this receptor for modulating dopamine output.     

A toxic shock syndrome toxin mutant of Staphylococcus aureus isolated by allelic replacement lacks virulence in a rabbit uterine model

The gene coding for toxic shock syndrome toxin-1 in S. aureus was inactivated by allelic replacement in two TSS-associated strains. One mutant derived from FRI1169 (a non-enterotoxigenic strain) lacked virulence in the rabbit uterine chamber infection model. This suggests that TSST-1 is the only determinant produced by this strain that can induce the symptoms of shock in rabbits. A novel method for allelic replacement involving transduction of plasmid integrants is described.     

Incorporation of 5-substituted uracil derivatives into nucleic acids. The isolation and gamma-radiation-sensitivity of bacteriophage T3 containing the thymine analogue 5-vinyluracil.

A compound with properties identical with the glucose-containing dolichyl diphosphate oligosaccharide present in animal tissues was detected in alfalfa roots incubated with [14C]glucose. The products of mild acid hydrolysis behaved the same on paper chromatography, on treatment with specific glucosidases and on N-deacetylation.     

Molecular weight,amino acid composition and other properties of membrane-bound ATPase fromBacillus megaterium KM

The Ca²⁺-activated ATPase fromBacillus megaterium KM has a molecular weight of 379000 as determined by sedimentation equilibrium in the analytical ultracentrifuge and 410000 as determined from sedimentation and diffusion coefficients. These values compare closely with molecular weights estimated for similar ATPases fromStreptococcus faecalis and mitochondria. On polyacrylamide gel electrophoresis in sodium dodecylsulfate two classes of subunit of molecular weight 68000 and 65000 are seen. They seem to be present in approximately equal proportion. The amino acid analysis gives a minimum molecular weight of 6250 and the amino acid composition is extremely close to that ofS. faecalis. The enzyme is denatured at 55°C and insensitive to oligomycin or ruthenium red in either the membrane-bound or soluble forms. The ATPase is estimated to comprise approximately 1% of the total cytoplasmic membrane protein.