Notes on the Chemotherapy of Hexarnitiasis

A method for controlled evaluation of drugs against Hexamita meleagridis in turkeys is presented. Experiments evaluating selected drugs and reevaluating all compounds and antibiotics previously reported to be efficacious against this species are described. Most of these compounds were tested against two separate isolates of this parasite, one from Indiana (1950) and the other from Wisconsin (1959). All preparations found effective against one isolate showed similar efficacy against the other. Conversely, preparations ineffective against one isolate were also ineffective against the other. Among the compounds showing efficacy were several antibiotics and dibutyl tin salts. Dibutyl tin dilaurate was found to have suitable efficacy at non-toxic dosage levels

Experiments on the Chemotherapy of Blackhead in Turkeys

Infectious enterohepatitis, or blackhead, is often regarded as the most important disease of turkeys since all ages and breeds are susceptible and mortality is high. The yearly financial losses resulting from blackhead have stimulated increasing interest and experimentation on chemotherapy of this disease. Many compounds have been tested, but at the present time no other group of compounds seems to offer as much promise as the organic arsenicals. Several members of this class of compounds as well as a few non-arsenicals have been found to have a limited effect against the blackhead organism; but none, whether arsenical or non-arsenical, has thus far found widespread practical use among turkey raisers

The Electric Conductivity of Kerosene and Gasoline as a Function of the Temperature

J. Herbert Jones in the Phil. Mag. for July, 1925, gives the results of experiments on The Influence of the Surrounding Medium on Frictional Electricity. In one of these experiments he uses pure paraffin oil which he heats by a coil of lead piping through which steam is blown. It was found that the resistance of the oil decreases steadily with a rise in temperature until the temperature reached 75°C. The resistance then seemed to remain fairly constant until the temperature rose further to 90°C. At this temperature the resistance seemed to break down suddenly

The Fluorescence of Cod Liver Oil

The fluorescence was produced by the radiation from a Cooper Hewitt quartz mercury vapor lamp. A Corex A blue purple filter was used to filter out that part of the spectrum of the exciting light in which the fluorescence appeared. The filtered light, which was almost entirely ultraviolet, was focused directly onto the surface of the cod liver oil by means of a quartz lens

Uprobe 2008: an online resource for universal overgo hybridization-based probe retrieval and design†

Cross-species sequence comparisons are a prominent method for analyzing genomic DNA and an ever increasing number of species are being selected for whole-genome sequencing. Targeted comparative genomic sequencing is a complementary approach to whole-genome shotgun sequencing and can produce high-quality sequence assemblies of orthologous chromosomal regions of interest from multiple species. Genomic libraries necessary to support targeted mapping and sequencing projects are available for more than 90 vertebrates. An essential step for utilizing these and other genomic libraries for targeted mapping and sequencing is the development of the hybridization-based probes, which are necessary to screen a genomic library of interest. The Uprobe website (http://uprobe.genetics.emory.edu) provides a public online resource for identifying or designing ‘universal’ overgo-hybridization probes from conserved sequences that can be used to efficiently screen one or more genomic libraries from a designated group of species. Currently, Uprobe provides the ability to search or design probes for use in broad groups of species, including mammals and reptiles, as well as more specific clades, including marsupials, carnivores, rodents and nonhuman primates. In addition, Uprobe has the capability to design custom probes from multiple-species sequence alignments provided by the user, thus providing a general tool for targeted comparative physical mapping

Interrupting peptidoglycan deacetylation during Bdellovibrio predator-prey interaction prevents ultimate destruction of prey wall, liberating bacterial-ghosts

The peptidoglycan wall, located in the periplasm between the inner and outer membranes of the cell envelope in Gram-negative bacteria, maintains cell shape and endows osmotic robustness. Predatory Bdellovibrio bacteria invade the periplasm of other bacterial prey cells, usually crossing the peptidoglycan layer, forming transient structures called bdelloplasts within which the predators replicate. Prey peptidoglycan remains intact for several hours, but is modified and then degraded by predators escaping. Here we show predation is altered by deleting two Bdellovibrio N-acetylglucosamine (GlcNAc) deacetylases, one of which we show to have a unique two domain structure with a novel regulatory-”plug”. Deleting the deacetylases limits peptidoglycan degradation and rounded prey cell “ghosts” persist after mutant-predator exit. Mutant predators can replicate unusually in the periplasmic region between the peptidoglycan wall and the outer membrane rather than between wall and inner-membrane, yet still obtain nutrients from the prey cytoplasm. Deleting two further genes encoding DacB/PBP4 family proteins, known to decrosslink and round prey peptidoglycan, results in a quadruple mutant Bdellovibrio which leaves prey-shaped ghosts upon predation. The resultant bacterial ghosts contain cytoplasmic membrane within bacteria-shaped peptidoglycan surrounded by outer membrane material which could have promise as “bacterial skeletons” for housing artificial chromosomes

Electrodeposited lead dioxide coatings

Lead dioxide coatings on inert substrates such as titanium and carbon now offer new opportunities for a material known for 150 years. It is now recognised that electrodeposition allows the preparation of stable coatings with different phase structures and a wide range of surface morphologies. In addition, substantial modification to the physical properties and catalytic activities of the coatings are possible through doping and the fabrication of nanostructured deposits or composites. In addition to applications as a cheap anode material in electrochemical technology, lead dioxide coatings provide unique possibilities for probing the dependence of catalytic activity on layer composition and structure (critical review, 256 references)

Activity of Bdellovibrio Hit Locus Proteins, Bd0108 and Bd0109, Links Type IVa Pilus Extrusion/Retraction Status to Prey-Independent Growth Signalling

Bdellovibrio bacteriovorus are facultatively predatory bacteria that grow within gram-negative prey, using pili to invade their periplasmic niche. They also grow prey-independently on organic nutrients after undergoing a reversible switch. The nature of the growth switching mechanism has been elusive, but several independent reports suggested mutations in the hit (host-interaction) locus on the Bdellovibrio genome were associated with the transition to preyindependent growth. Pili are essential for prey entry by Bdellovibrio and sequence analysis of the hit locus predicted that it was part of a cluster of Type IVb pilus-associated genes, containing bd0108 and bd0109. In this study we have deleted the whole bd0108 gene, which is unique to Bdellovibrio, and compared its phenotype to strains containing spontaneous mutations in bd0108 and the common natural 42 bp deletion variant of bd0108. We find that deletion of the whole bd0108 gene greatly reduced the extrusion of pili, whereas the 42 bp deletion caused greater pilus extrusion than wild-type. The pili isolated from these strains were comprised of the Type IVa pilin protein; PilA. Attempts to similarly delete gene bd0109, which like bd0108 encodes a periplasmic/secreted protein, were not successful, suggesting that it is likely to be essential for Bdellovibrio viability in any growth mode. Bd0109 has a sugar binding YD- repeat motif and an N-terminus with a putative pilin-like fold and was found to interact directly with Bd0108. These results lead us to propose that the Bd0109/Bd0108 interaction regulates pilus production in Bdellovibrio (possibly by interaction with the pilus fibre at the cell wall), and that the presence (and possibly retraction state) of the pilus feeds back to alter the growth state of the Bdellovibrio cell. We further identify a novel small RNA encoded by the hit locus, the transcription of which is altered in different bd0108 mutation background

MIDA boronates are hydrolysed fast and slow by two different mechanisms

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for small-molecule construction based on building blocks, largely because of the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, which has hindered efforts to address the current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base mediated and the other neutral. The former can proceed more than three orders of magnitude faster than the latter, and involves a rate-limiting attack by a hydroxide at a MIDA carbonyl carbon. The alternative 'neutral' hydrolysis does not require an exogenous acid or base and involves rate-limiting B-N bond cleavage by a small water cluster, (H2O)n. The two mechanisms can operate in parallel, and their relative rates are readily quantified by (18)O incorporation. Whether hydrolysis is 'fast' or 'slow' is dictated by the pH, the water activity and the mass-transfer rates between phases. These findings stand to enable, in a rational way, an even more effective and widespread utilization of MIDA boronates in synthesis