Seeing better through a MIST: evaluation of monoclonal recombinant antibody fragments on microarrays

Automation is the key approach for genomewide and proteomewide screening of function and interaction. Especially for proteomics, antibody microarrays are a useful tool for massive parallel profiling of complex samples. To meet the requirements of antibody microarrays and to obtain a great variety of antibodies, new technologies such as phage display have partly replaced the classical hybridoma method. While the selection process for phage-displayed antibody fragments itself has been automated, the bottleneck was shifted further downstream to the identification of monoclonal binders obtained from the selections. Here, we present a new approach to reduce time, material, and waste to extend automation beyond the selection process by application of conventional microarray machinery. We were able to express recombinant antibody fragments in a single inoculation and expression step and subjected them without purification directly to an automated high-throughput screening procedure based on the multiple spotting technique (MIST). While obtaining comparable sensitivities to enzyme-linked immunosorbent assays, we minimized manual interaction steps and streamlined the technique to be accessible within the automated selection procedure.     

Nonlinear Faraday rotation for optical limitation

The possible use of the nonlinear Faraday effect for optical limitation of the laser power is investigated in a resonant Faraday medium placed between two crossed polarizers. The results are comparable with those obtained at strong magnetic fields as a result of the linear Faraday effect. Advantages of the method are the narrow bandwidth and the wide field of view. The investigations are interesting from the viewpoint of applications for optical sensor protection and automation of the experiment. All measurements are performed at the F(g) = 2 --> F(e) = 1 hyperfine structure transition of the 87Rb D1 line.     

Spatial light modulator-controlled alignment and spinning of birefringent particles optically trapped in an array

We demonstrate the use of a phase-only liquid-crystal spatial light modulator (SLM) for polarization-controlled rotation and alignment of an array of optically trapped birefringent particles. A collimated beam incident upon a two-dimensional lenslet array yields multiple foci, scaled to produce optical gradient traps with efficient three-dimensional trapping potentials. The state of polarization of each trapping beam is encoded by the SLM, which acts as a matrix of wave plates with computer-controlled phase retardations. Control of the rotation frequency and alignment direction of the particles is achieved by the transfer of tunable photon spin angular momentum.     

Comment: Influence of illuminating beyond the object support on Zernike-type phase contrast filtering

In this comment, we clarify some serious misinterpretations that can arise from an uncritical use of the results presented in [Appl. Opt. 41, 2607, (2002)]. In particular, we point out that their suggestion of using "illumination beyond the object support" for measuring phase disturbances can result in distorted or strongly inaccurate interference patterns. We also point out that Llave and Castillo have misinterpreted our previous work describing the effect of phase object fill factor on the output interference patterns, which is in fact one of the key factors considered in the generalized phase contrast (GPC) method. Unlike the Zernike method, the GPC method results in an optimized visualization of the phase disturbance by the achievement of a matching condition between the applied filter and the spatial average of a given phase disturbance, thereby implying the optimal use of fill factor information.     

Sympathetic activation triggers systemic interleukin-10 release in immunodepression induced by brain injury

The mechanism of immunodepression after brain injury is not yet clear. Here we demonstrate rapid systemic release of the immunoinhibitory cytokine interleukin-10, monocytic deactivation and a high incidence of infection in patients with 'sympathetic storm' due to acute accidental or iatrogenic brain trauma. In vitro studies showed that within minutes catecholamines trigger the secretion of interleukin-10 from unstimulated monocytes through a beta-adrenoreceptor-mediated, cAMP/protein kinase A-dependent pathway. We found that in a rat model of acute brain injury, the beta-receptor antagonist propranolol prevented the increase of interleukin-10 plasma levels. Rapid monocytic interleukin-10 release after sympathetic activation may represent a common pathway for immunodepression induced by stress and injury.