On-line infrared spectroscopy for bioprocess monitoring

One of the major aims of bioprocess engineering is the real-time monitoring of important process variables. This is the basis of precise process control and is essential for high productivity as well as the exact documentation of the overall production process. Infrared spectroscopy is a powerful analytical technique to analyze a wide variety of organic compounds. Thus, infrared sensors are ideal instruments for bioprocess monitoring. The sensors are non-invasive, have no time delay due to sensor response times, and have no influence on the bioprocess itself. No sampling is necessary, and several components can be analyzed simultaneously. In general, the direct monitoring of substrates, products, metabolites, as well as the biomass itself is possible. In this review article, insights are provided into the different applications of infrared spectroscopy for bioprocess monitoring and the complex data interpretation. Different analytical techniques are presented as well as example applications in different areas.     

Reduction potential variations in azurin through secondary coordination sphere phenylalanine incorporations

Recent evidence has shown that the properties of metal binding sites can be tuned by more than the ligands in the primary coordination sphere. We investigated the incorporation of four phenylalanine residues into the secondary coordination sphere of the small soluble blue copper protein azurin. The locations for placement of these residues in azurin were based on the structure of the highly hydrophobic blue copper protein rusticyanin, which is known to have a significantly higher reduction potential than azurin. Using site-directed mutagenesis, these residues in close proximity to the copper binding site were mutated to large hydrophobic phenylalanine residues individually and in combination. We also added the Met121Leu mutation on top of the Phe mutations to construct a total of 13 variants. We found little change in the UV-visible absorption and EPR data for these proteins, however modest increases in reduction potential were observed with increases by as much as 30 mV per Phe residue. Furthermore, we observed the increases in potential to be additive.     

<Emphasis Type="Italic">TRAF1/C5</Emphasis>polymorphism is not associated with increased mortality in rheumatoid arthritis: two large longitudinal studies

Introduction  

Recently an association between a genetic variation in TRAF1/C5 and mortality from sepsis or cancer was found in rheumatoid arthritis (RA). The most prevalent cause of death, cardiovascular disease, may have been missed in that study, since patients were enrolled at an advanced disease stage. Therefore, we used an inception cohort of RA patients to investigate the association between TRAF1/C5 and cardiovascular mortality, and replicate the findings on all-cause mortality. As TRAF1/C5 associated mortality may not be restricted to RA, we also studied a large cohort of non-RA patients.     

Mesenchymal stem cells in autoimmune diseases: hype or hope?

Intervention with mesenchymal stem cells (MSCs) represents a promising therapeutic tool in treatment-refractory autoimmune diseases. A new report by Schurgers and colleagues in a previous issue of Arthritis Research & Therapy sheds novel mechanistic insight into the pathways employed by MSCs to suppress T-cell proliferation in vitro, but, at the same time, indicates that MSCs do not influence T-cell reactivity and the disease course in an in vivo arthritis model. Such discrepancies between the in vitro and in vivo effects of potent cellular immune modulators should spark further research and should be interpreted as a sign of caution for the in vitro design of MSC-derived interventions in the setting of human autoimmune diseases.     

Serum electrophoretic patterns of karyotypically defined owl monkeys (Aotus trivirgatus).

Sera were electrophoretically separated and examined from 238 karyotyped Aotus trivirgatus and 29 unkaryotyped offspring. Albumin polymorphism was observed with high frequency and found to conform to a codominant allele mode of transmission. A unique alpha globulin was identified in Karyotypes I, VII and unkaryotyped offspring, of which one parent was a Karyotype I. This alpha globulin phenotype appears to be a dominant characteristic.     

Identification of the IL-17 receptor related molecule IL-17RC as the receptor for IL-17F

The proinflammatory cytokines IL-17A and IL-17F have a high degree of sequence similarity and share many biological properties. Both have been implicated as factors contributing to the progression of inflammatory and autoimmune diseases. Moreover, reagents that neutralize IL-17A significantly ameliorate disease severity in several mouse models of human disease. IL-17A mediates its effects through interaction with its cognate receptor, the IL-17 receptor (IL-17RA). We report here that the IL-17RA-related molecule, IL-17RC is the receptor for IL-17F. Notably, both IL-17A and IL-17F bind to IL-17RC with high affinity, leading us to suggest that a soluble form of this molecule may serve as an effective therapeutic antagonist of IL-17A and IL-17F. We generated a soluble form of IL-17RC and demonstrate that it effectively blocks binding of both IL-17A and IL-17F, and that it inhibits signaling in response to these cytokines. Collectively, our work indicates that IL-17RC functions as a receptor for both IL-17A and IL-17F and that a soluble version of this protein should be an effective antagonist of IL-17A and IL-17F mediated inflammatory diseases.     

Characterization of the immuno-regulatory response to the tapeworm Hymenolepis diminuta in the non-permissive mouse host

Hymenolepis diminuta is spontaneously expelled from mice; concomitant with worm expulsion was protection against colitis induced by dinitrobenzene sulphonic acid (DNBS). Here we examined the immune response mobilized by Balb/c and C57Bl/6 male mice in response to H. diminuta and assessed the requirement for CD4+ cells (predominantly T cells) in worm expulsion and the anti-colitic effect. Wild-type (CD4+) or CD4 knock-out (CD4-/-) mice received five H. diminuta cysticercoids and segments of jejunum and mesenteric lymph nodes (MLNs), or spleen, were excised 5, 8 and 1l days later for mRNA analysis and cytokine production, respectively. In separate experiments uninfected and infected mice received DNBS by intra-rectal infusion and indices of inflammation were assessed 3 days later (i.e. 11 days p.i.). Infection of Balb/c mice resulted in a time-dependent increase in intestinal mRNA for Foxp3, a marker of natural regulatory T cells, and markers of alternatively activated macrophages (arginase-1, FIZZ1), while concanavalin-A activation of MLN cells revealed a significant increase in T helper 2 (TH2) type cytokines: IL-4, -5, -9, -10, -13. MLN cells showed a reduced ability to induce Foxp3 expression upon stimulation. CD4-/- mice did not display this response to infection, but surprisingly did expel H. diminuta. Moreover, DNBS-induced colitis in CD4-/- mice (wasting, tissue damage, elevated myeloperoxidase) was not reduced by H. diminuta infection, whereas time-matched infected CD4+ C57Bl/6 mice had significantly less DNBS-induced inflammation. In conclusion: (i) in addition to stereotypical TH2 events, H. diminuta-infected Balb/c mice develop a local immuno-regulatory response; and (ii) CD4+ cells are not essential for H. diminuta expulsion from mice but are critical in mediating the anti-colitic effect that accompanies infection in this model.