Immunoglobulin G galactosylation and sialylation are associated with pregnancy-induced improvement of rheumatoid arthritis and the postpartum flare: results from a large prospective cohort study

Introduction  

Improvement of rheumatoid arthritis (RA) during pregnancy has been causatively associated with increased galactosylation of immunoglobulin G (IgG) N-glycans. Since previous studies were small, did not include the postpartum flare and did not study sialylation, these issues were addressed in the present study.     

Impact of heparan sulfate chains and sulfur-mediated bonds on the mechanical properties of bovine lens capsule

We assessed the importance of glycosaminoglycans and sulfur-mediated bonds for the mechanical properties of lens capsules by comparing the stress-strain responses from control and treated pairs of bovine source. No significant change in mechanical properties was observed upon reduction of disulfide bonds. However, removal of glycosaminoglycan chains resulted in a significantly stiffer lens capsule, whereas high concentrations of reducing agent, which is expected to reduce the recently reported sulfilimine bond of collagen IV, resulted in a significantly less stiff lens capsule. A comparison of the diffraction patterns of the control and strongly reduced lens capsules indicated structural rearrangements on a nanometer scale.     

Measuring sub-lethal effects on freshwater crayfish (<Emphasis Type="Italic">Paranephrops planifrons</Emphasis>) behaviour and physiology: laboratory and in situ exposure to modified zeolite

Various behavioural and physiological tests were applied to determine whether an aluminised modified zeolite clay product (Z2G1), used to cap phosphorus release from lake sediments, had sub-lethal effects on adult freshwater crayfish (Paranephrops planifrons). In situ exposures of caged crayfish before and after application of modified zeolite to Lake Okaro, Central North Island, New Zealand, at a nominal application concentration of 350 g m⁻², did not impact the survival of freshwater crayfish or produce any significant sub-lethal effects on crayfish mobility or physiology that we could detect. In laboratory sediment tests, crayfish did not show any consistent effect from short-term (10 days) exposure to modified zeolite (at concentrations of 350, 700 or 2,100 g m⁻²) or to alum. When combined, the field and laboratory data provide strong evidence that applications of 350 g m⁻² modified zeolite will have no short-term effect on adult crayfish, with a ‘margin of safety’ for higher application rates. Chronic exposure effects of capping agents and the indirect impacts of lake treatment (e.g. food web responses) are yet to be determined. Quantitative measures of shade- and shelter-seeking behaviour, righting behaviour, and length of escape response, could be improved by the addition of standardised behavioural observations. Physiological measures of ammoniacal-N production and oxygen consumption are less variable than behavioural tests, but comparisons between treatments are best conducted simultaneously. A suite of behavioural and physiological sub-lethal measures using field and laboratory exposures is recommended to provide an integrated assessment of crayfish health.     

Genomics by the beach

A report on the 35th Annual Lorne Genome Conference 2014 held in Lorne, Victoria, Australia, February 16–18, 2014.     

Flexible Community Structure Correlates with Stable Community Function in Methanogenic Bioreactor Communities Perturbed by Glucose

Methanogenic bioreactor communities were used as model ecosystems to evaluate the relationship between functional stability and community structure. Replicated methanogenic bioreactor communities with two different community structures were established. The effect of a substrate loading shock on population dynamics in each microbial community was examined by using morphological analysis, small-subunit (SSU) rRNA oligonucleotide probes, amplified ribosomal DNA (rDNA) restriction analysis (ARDRA), and partial sequencing of SSU rDNA clones. One set of replicated communities, designated the high-spirochete (HS) set, was characterized by good replicability, a high proportion of spiral and short thin rod morphotypes, a dominance of spirochete-related SSU rDNA genes, and a high percentage of Methanosarcina-related SSU rRNA. The second set of communities, designated the low-spirochete (LS) set, was characterized by incomplete replicability, higher morphotype diversity dominated by cocci, a predominance of Streptococcus-related and deeply branching Spirochaetales-related SSU rDNA genes, and a high percentage of Methanosaeta-related SSU rRNA. In the HS communities, glucose perturbation caused a dramatic shift in the relative abundance of fermentative bacteria, with temporary displacement of spirochete-related ribotypes by Eubacterium-related ribotypes, followed by a return to the preperturbation community structure. The LS communities were less perturbed, with Streptococcus-related organisms remaining prevalent after the glucose shock, although changes in the relative abundance of minor members were detected by morphotype analysis. A companion paper demonstrates that the more stable LS communities were less functionally stable than the HS communities (S. A. Hashsham, A. S. Fernandez, S. L. Dollhopf, F. B. Dazzo, R. F. Hickey, J. M. Tiedje, and C. S. Criddle, Appl. Environ. Microbiol. 66:4050–4057, 2000).     

A 17S multiprotein form of murine cell DNA polymerase mediates polyomavirus DNA replication in vitro

We have identified and purified a multiprotein form of DNA polymerase from the murine mammary carcinoma cell line (FM3A) using a series of centrifugation, polyethylene glycol precipitation, and ion-exchange chromatography steps. Proteins and enzymatic activities associated with this mouse cell multiprotein form of DNA polymerase include the DNA polymerases α and δ, DNA primase, proliferating cell nuclear antigen (PCNA), DNA ligase I, DNA helicase, and DNA topoisomerases I and II. The sedimentation coefficient of the multiprotein form of DNA polymerase is 17S, as determined by sucrose density gradient analysis. The integrity of the murine cell multiprotein form of DNA polymerase is maintained after treatment with detergents, salt, RNase, DNase, and after chromatography on DE52-cellulose, suggesting that the association of the proteins with one another is independent of nonspecific interaction with other cellular macromolecular components. Most importantly, we have demonstrated that this complex of proteins is fully competent to replicate polyomavirus DNA in vitro. This result implies that all of the cellular activities required for large T-antigen dependent in vitro polyomavirus DNA synthesis are present within the isolated 17S multiprotein form of the mouse cell DNA replication activities. A model is proposed to represent the mammalian Multiprotein DNA Replication Complex (MRC) based on the fractionation and chromatographic profiles of the individual proteins found to co-purify with the complex.     

Case of Clostridium perfringens bacteremia after routine colonoscopy and polypectomy

Bacteremia is an uncommon complication after polypectomy and colonoscopy. We report one of the first cases of Clostridium perfringens bacteremia after polypectomy. Our patient was a four years old boy with congenital polyposis, who underwent colonoscopy and polypectomy without complication. Approximately 12 h later he developed a fever and tachycardia with no other clinical symptoms. His blood cultures grew out penicillin susceptible C. perfringens and Enterococcus faecalis. He responded to antibiotic therapy and remained clinically asymptomatic for the duration of his course. There are a few reports of bacteremia after routine polypectomy, but no reported cases of C. perfringens bacteremia in the pediatric population. Clostridial sp. bacteremia can be fatal with devastating consequences if appropriate antibiotics and/or surgical debridement are delayed. Polymicrobial infection, as illustrated in our patient, is also common and can be a poor prognostic risk factor. Therefore, for patients with a history of polypectomy and new onset fever, anaerobic infections should be considered and empiric antibiotic therapy should include coverage for these organisms.     

Detection of bacteriocins of lactic acid bacteria isolated from foods and comparison with pediocin and nisin

A total of 663 533 colonies from 72 dairy and meat sources showed a detection rate of 0·2% for bacteriocin producers using direct plating techniques. A further 83 000 colonies from 40 fish and vegetable sources showed a detection rate of 3·4% for bacteriocin producers using selective enrichment procedures. A collection of seven purified isolates showing a different host spectrum of bacteriocin activity and with the ability to produce bacteriocins in broth culture were compared with nisin and pediocin (with respect to their inhibitory activity, determined by the critical dilution method), against various indicator bacteria in agar and broth. The sensitivity of Listeria species to various bacteriocins was influenced by the agar and broth test systems used. A Lactobacillus curvatus strain was found to be the most suitable indicator for quantitating antimicrobial effects of all the bacteriocins investigated in both agar and broth test systems. The bacteriocin-producing isolates were characterized by biochemical reactions and DNA restriction enzyme profiles and taxonomic identification revealed species of Lactobacillus , Carnobacterium and Lactococcus assigned on the basis of 16S rDNA sequences.