Inertial focusing of ellipsoidal Euglena gracilis cells in a stepped microchannel.

Euglena gracilis (E. gracilis) has recently been attracting attention as a potential renewable source for the production of biofuels, livestock feed, cosmetics, and dietary supplements. Research has focused on strain isolation, productivity improvement, nutrient and resource allocation, and co-product production, key steps that ultimately determine the economic viability and compatibility of the biomass produced. To achieve these characteristics, approaches to select E. gracilis mutants with desirable properties, such as high wax ester content, high growth rate, and high environmental tolerance for biodiesel and biomass production, are needed. Flow-based analysis and sorting can be rapid and highly automated but calls for techniques that can precisely control the position of E. gracilis with varying sizes and shapes in a tightly focused stream in a high-throughput manner. In this work, we use a stepped microchannel consisting of a low-aspect-ratio straight channel and a series of expansion regions along the channel height. We study horizontal and vertical focusing, orientation, rotational, and translational behaviors of E. gracilis as a function of aspect ratio (AR) and channel Reynolds number (Re). By making use of inertial focusing and local secondary flows, E. gracilis with diverse shapes are directed to a single equilibrium position in a single focal stream. As an application of on-chip flow cytometry, we integrate a focusing microchip with a custom laser-two-focus (L2F) optical system and demonstrate the detection of chlorophyll autofluorescence as well as the measurement of the velocity of E. gracilis cells flowing through the microchannel.

Agalactosyl IgG is elevated in patients with active spondyloarthropathy.

Patients with rheumatoid arthritis or with Crohn's disease have deficient galactosylation of serum IgG [Gal(0)]. To study whether such deviation occurs in patients with spondyloarthropathy (SPA), we studied the percentage incidence of Gal(0) corrected for age [Gal(0)corr] in 47 SPA patients undergoing ileocolonoscopy and correlated the findings with clinical variables and prognosis of the patients. Gal(0)corr was elevated in 36% of the patients. Such patients had a higher number of inflamed joints (P < 0.02), higher ESR (P < 0.001) and CRP (P < 0.001). Elevated Gal(0)corr was also of prognostic significance: at 6-month follow-up those with elevated levels had a higher number of inflamed joints (P < 0.02) and ESR (P < 0.05). The presence of high Gal(0)corr did not associate with gut inflammation. In conclusion, a proportion of SPA patients has elevated levels of Gal(0), the amount of which correlates with severity of the disease and is a prognostic marker for chronicity of the disease.

IgA and IgG antibodies to distinct serotypes of Mycobacterium avium in HIV seropositivity and AIDS.

IgA and IgG antibodies to cytoplasmic and secreted antigens of serotypes 4 and 8 of Mycobacterium avium and the percentage of agalactosyl immunoglobulin (%Gal[0]) were measured by ELISA in groups of blood donors, HIV seronegative persons, HIV seropositive persons with CD4+ cell counts >300/mm3 and AIDS patients co-infected with M.avium. No differences were found between the control groups, but HIV seropositive persons were distinguished by their increased %Gal[0] (p<0.001) and increased IgA titre (p<0.05) to secreted antigens of both serotypes of M. avium. Patients going on to develop aviumosis differed from other HIV-positive individuals, having more IgA to secreted antigens of serotype 8 (p<0.03) and more IgG to secreted antigens of both serotypes (p<0.0001), IgA titres fell to both types of antigen from serotype 4 (p<0.01) and sonicate antigen of serotype 8 (p<0.001) and IgG fell to the secreted antigens of serotype 4 (p<0.03). On interpretation of these observations that antibody profiles to M. avium might be used to identify healthy persons at special risk of developing HIV seropositivity, and to identify persons with early AIDS who are likely to develop aviumosis.