Guanidination of a peptide side chain amino group on a solid support

A novel guanidination method of converting a peptide side chain amino group to a guanidino group on a solid support is described. Four guanidinating reagents were evaluated using a model tetrapeptide attached to a polystyrene resin. Experimental data indicate that the two nitroguanidinating reagents, but not the two tosylguanidinating reagents, can be used effectively in solid phase peptide synthesis.     

Molecular pharmacology of muscarinic receptor heterogeneity

Muscarinic receptors can be pharmacologically classified into 3 types at the present time, however, five genes for the receptor have been identified. The muscarinic receptor types have unique antagonist selectivity, distribution and are linked to specific second messenger systems. The interaction between the muscarinic receptor types and G proteins may depend on the systems in which the receptors are integrated. Expression of the cloned gene in mammalian cells will be useful in delineating the relationships between the pharmacological types of muscarinic receptors and their genes and studying the interactions between the receptor, G proteins, and second messenger coupling.     

Progress in treatment of ANCA-associated vasculitis

Autoantibodies to neutrophil cytoplasmic antigen-associated vasculitis (AAV) is characterised by inflammation of blood vessels. The introduction of immunosuppressive therapy with glucocorticoids and cyclophosphamide transformed AAV from a fatal condition to a largely treatable condition. Over the past 30 years, considerable progress has been made refining immunosuppressive regimens with a focus on minimising toxicity. There is, however, a high unmet need in the treatment of AAV. A proportion of patients are refractory to current therapies; 50% experience a relapse within 5 years and treatment toxicity contributes to mortality and chronic disability. As knowledge of the pathogenesis of vasculitis grows, it is mirrored by the availability of biological agents, which herald a revolution in the treatment of vasculitis. Lymphocyte-targeted and cytokine-targeted agents have been evaluated for the treatment of AAV and are entering the routine therapeutic arena with the potential to improve patient outcomes. As rare diseases, treatment advances in vasculitis depend on international collaborative research networks both to establish an evidence base for newer agents and to develop recommendations for patient management.     

Changes in maize-stalk proteins during ear development

Although the stalk of maize ( Zea mays L.) functions as a reservoir for N, little is known of qualitative changes which accompany the remobilization of N to the developing ear. SDS-PAGE analysis revealed that certain stalk proteins were lost, whereas others were not. The removal of ears and the prevention of pollination eliminated the selective protein loss. The use of ¹⁵N labelling showed that some stalk-protein fractions turned over faster with ear development, whereas the turnover of others was unchanged or slowed. The data indicate that at least 7 proteins function as temporary storage forms of N in the stalk, and that they are degraded during the first 3 weeks after silking to provide organic N for ear development.     

The binding of barium and calcium ions by the antibiotic beauvericin

The ion-transporting antibiotic beauvericin has been shown to have a high affinity for calcium and barium ions in addition to the more usual affinity for monovalent cations. As judged by crystallization, extraction into organic solvent, and U-tube transport the cation selectivity is Rb>Ba>K>Na?Ca?Li. For these studies an improved method for the synthesis of beauvericin has been developed.     

Synthesis of optically pure C alpha-methyl-arginine.

Optically pure L-(+)-C alpha-methyl-arginine and D-(-)-C alpha-methyl-arginine were synthesized. Experimental results indicated that DL-C alpha-methyl-arginine methyl ester could be resolved by trypsin, but workup posed a technical difficulty. Chemical resolution at the stage of DL-C alpha-methyl-ornithine, followed by selective guanidination using N,N'-di-Cbz-S-methylisothiourea and hydrogenolysis provided a effective and practical method for the synthesis of optically pure C alpha-methyl-arginine.     

The molecular organization of the beta-globin complex of the deer mouse, Peromyscus maniculatus

Recombinant DNA clones have been isolated that contain 80 kb of the beta-globin complex from the deer mouse, Peromyscus maniculatus. Comparisons of this complex with that from the laboratory mouse, Mus domesticus (with an order 5'-Hbby, Hbb-bhO, Hbb-bhl, Hbb-bh2, Hbb-bh3, Hbb-bl, Hbb-b2 3') highlight organizational trends in the beta-globin complex since the two species diverged. Unlike other mammals studied thus far, the deer mouse possesses three adult genes. Partial sequence analysis indicates that each of the three adult genes is intact and hence may be functional. Hybridization of one of the two Mus pseudogenes, Hbb-bh3, to genomic blots from Peromyscus reveals that it has a homologous counterpart in Peromyscus. Homologous genes to the two gamma-like Mus genes, Hbb-bhO and Hbb-bhl, are also found in Peromyscus. The strong hybridization between the Hbb-bhl genes and significant nucleotide similarity between the Hbb-bhO genes suggest that both pairs are important for the ontogeny of these mice although no known product has been identified for the Hbb-bhO genes. The presence of Hbb-bhO and Hbb-bhl in Peromyscus suggests that the duplication that created this related gene set occurred before the two lineages diverged. A single gene for Hbb-y has been isolated from Peromyscus. The adult region in Peromyscus has undergone significant divergence from the same region in Mus, having three rather than two adult genes, the acquisition of at least 15 kb of extra DNA relative to Mus, and possibly the loss of the Hbb-bh2 pseudogene. The nonadult region of the complex, in contrast, contains the same set of genes apparently distributed over the same amount of DNA as in the Mus beta- globin complex. This observation suggests that the embryonic region of the complex is more evolutionarily stable than the adult region.      

Prevalence of Prototheca spp. on dairy farms in Poland – a cross-country study

The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Here, we present results of a first large-scale, cross-country survey on the prevalence of Prototheca spp. in dairy cows, and their environment in Poland. A total of 1211 samples were collected and microbiologically analysed. Included within this number were milk (n = 638), body swabs (n = 374) and environmental samples (n = 199), originating from 400 dairy cows and their surroundings, on 16 dairy farms, based in all major provinces of the country. Prototheca spp. were the third, after Streptococcus and Staphylococcus spp., most common mastitis pathogens. The overall prevalence of protothecal mastitis was 8.3% (33/400), with the majority (75.8%) of cases having a subclinical course, and all but one attributable to P. zopfii genotype 2. Prototheca spp. were cultured from body swabs of both healthy and mastitic cows, yet the isolation rate among the latter was conspicuously lower (12.3% vs. 17.8%). Forty-two (21.2%) environmental samples yielded growth of Prototheca spp. However, no clear association between Prototheca mastitis in dairy cows and the algal isolation from the herd environment was found. Nor was there any association between the environmental recovery of the algae and farm management practices.