Understanding the role of different strain types of Fusobacterium necrophorum: biofilms, glycans and metabolic pathways

Fusobacterium necrophorum an obligate Gram-negative anaerobe has been implicated in the cause of persistent severe throat infections and the systemic life-threatening Lemierre’s syndrome; a potentially fatal periodontal disease, which results in abscess formation in the tonsils. The use of antibiotics had led to decreased incidence of F. necrophorum infections to a point that the bacterium became a forgotten pathogen; however, there has recently been a rise in interest. F. necrophorum is thought to survive the aerobic oropharynx by biofilm formation. Studies of optimal conditions for biofilm formation could be useful in improving therapeutic options. This current study determined that strains ARU 01 and JCM 3718 formed the most biofilm at 37 °C, with reduction in biofilm observed at 26 °C and 42 °C. Strain JCM 3724 on the other hand, formed most biofilm at 26 °C and 42 °C; this is an indication that strain JCM 3724 but not JCM 3718 or ARU 01 was able to survive in extreme temperatures by forming biofilms; all strains produced more biofilm at pH 4. Biofilm formation was observed in both mono and dual species culture of F. necrophorum, in dual culture the organisms became resistant to penicillin and ciprofloxacin. As glycans are implicated in biofilm formation, bacterial adhesion to host cells and pathogenicity, the cell surface glycans and cell extracts of F. necrophorum were investigated using enzyme-linked lectin assays (ELLA) and lectin histochemical staining. No significant differences were seen in the staining patterns, but a patchy and variable staining was noted for Sambucus nigra that detects sialic acid. A surface lectin, the Galactose binding protein was identified and characterised as binding to unsubstituted beta galactosyl residues of the type carried by many bacteria suggesting a role in biofilm formation. Subsequent molecular and bioinformatic studies identified all but one key component of the lipid A pathway; lpxI was shown to substitute for lpxH in the pathway. The component genes required for expression of sialic acid on the cell surface of the organism were determined; a polymorphism, the presence or absence of siaA, suggested some but not all strains had the ability to express this sugar on the cell surface. Further studies are required to determine whether this is linked to pathogenicity. Genomic and proteomic studies on type strains and clinical isolates revealed significant differences between subsp. necrophorum and funduliforme that will be useful in developing a simple molecular based subspeciation test. The subsp. funduliforme was split into 3 clusters (A, B and C) based on the genomic data; proteomic studies were used to determine the impact of the non-synonymous SNPs seen; two clusters were observed at the protein level, A and B+C. Most of the amino acid replacements that differentiated the clusters A from B +C were conservative or semi- conservative; more differences were noted between the two subspecies and these also included non-conservative changes that could affect protein structure and function. Clearly, there is scope for further work to elucidate the evolution of these clusters and their relevance to pathogenicity

Determination of Trace Elements in the Sakumo Wetland Sediments

Abstract: The objective of this research was to determine the current pollution status of the Sakumo wetland with the aim of identifying factors affecting the long-term integrity of the wetland ecosystem. Sediment samples from the Sakumo wetland were analysed for Cd, Co, Cr, Cu, Fe, Ni, Mn and Zn using Instrumental Neutron Activation Analysis (INAA) coupled with the conventional counting system. The sediment materials exhibited higher concentrations of trace elements Cd (maximum; 0.041 mg/kg), Co (maximum; 0.64 mg/kg), Cr (maximum; 30.73 mg/kg), Cu (maximum; 22.89 mg/kg), Ni (maximum; 11.69 mg/kg) and Zn (maximum; 6.52 mg/kg). In some of the lagoon sediments compared with their levels in world average soils, the average concentrations of the trace elements in general are below or within levels in world average soils/uncontaminated soils. Concentrations of Ni showed positive correlation with Cr whilst Co correlated positively with Cr and Zn. However, lack of correlation between Fe and Cd, suggests that the influence of these parameters on the distribution of trace metals is not important

Reticular synthesis and the design of new materials

The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures, compositions and properties. In particular, highly porous frameworks held together by strong metal-oxygen-carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62718/1/nature01650.pd

Contribution of Human Muscle-Derived Cells to Skeletal Muscle Regeneration in Dystrophic Host Mice

Background: Stem cell transplantation is a promising potential therapy for muscular dystrophies, but for this purpose, the cells need to be systemically-deliverable, give rise to many muscle fibres and functionally reconstitute the satellite cell niche in the majority of the patient's skeletal muscles. Human skeletal muscle-derived pericytes have been shown to form muscle fibres after intra-arterial transplantation in dystrophin-deficient host mice. Our aim was to replicate and extend these promising findings.Methodology/Principal Findings: Isolation and maintenance of human muscle derived cells (mdcs) was performed as published for human pericytes. Mdscs were characterized by immunostaining, flow cytometry and RT-PCR; also, their ability to differentiate into myotubes in vitro and into muscle fibres in vivo was assayed. Despite minor differences between human mdcs and pericytes, mdscs contributed to muscle regeneration after intra-muscular injection in mdx nu/nu mice, the CD56+ sub-population being especially myogenic. However, in contrast to human pericytes delivered intra-arterially in mdx SCID hosts, mdscs did not contribute to muscle regeneration after systemic delivery in mdx nu/nu hosts.Conclusions/Significance: Our data complement and extend previous findings on human skeletal muscle-derived stem cells, and clearly indicate that further work is necessary to prepare pure cell populations from skeletal muscle that maintain their phenotype in culture and make a robust contribution to skeletal muscle regeneration after systemic delivery in dystrophic mouse models. Small differences in protocols, animal models or outcome measurements may be the reason for differences between our findings and previous data, but nonetheless underline the need for more detailed studies on muscle-derived stem cells and independent replication of results before use of such cells in clinical trials

The Photolytic Cleavage of Methylpyridinecobaloxime [Co(CH3)(dmgH)2(py)] as a Mimetic of Vitamin B12

The photolytic reactions of the methylpyridinecobaloxime, Co(CH3)(dmgH)2(py) were examined first in benzene and then in a mixture of acetonitrile, hydrogen peroxide and toluene using sunlight and 450 Watts Hanovia UV lamp. While in the first, toluene was produced, the later produced a mixture of products that is o, p, m cresol and benzaldehyde. The photolytic reaction of vitamin B12 (methylcobalamin) was also examined in benzene and hydrogen peroxide using sunlight. Phenol was produced. All the products formed were separated and characterized by IR and GC–MS. The formation of these products indicates that hydroxyl radicals were generated analogous to Fenton reaction and that both vitamin B12 (methylcobalamin) and methylpyridinecobaloxime, Co(CH3)(dmgH)2(py) undergoesthe same photolytic cleavage of the Co-C bond