Ultra-Fast Impedimetric Immunoassay for Detection of Streptococcus agalactiae Using Carbon Electrode with Nanodiamonds Film.

This publication presents the results of work on the development of a quick and cheap electrochemical immunosensor for the diagnosis of infections with the pathogen Streptococcus agalactiae. The research was carried out on the basis of the modification of the well-known glassy carbon (GC) electrodes. The surface of the GC (glassy carbon) electrode was covered with a film made of nanodiamonds, which increased the number of sites for the attachment of anti-Streptococcus agalactiae antibodies. The GC surface was activated with EDC/NHS (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-Hydroxysuccinimide). Determination of electrode characteristics after each modification step, performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).

Screening of subclinical P300 event-related potentials changes in childhood acute lymphoblastic leukemia survivors.

Modern treatment of childhood acute lymphoblastic leukemia (ALL) has resulted in a high cure rate; however, it can cause central nervous system toxicity. In the present study, a group of 136 ALL survivors were screened for changes in P300. Therapy was conducted according to a modified New York (NY) protocol (30 patients) and two subsequent revisions of a modified Berlin-Frankfurt-Münster (BFM) protocol (32 and 74 patients). The control group consisted of 58 patients. The survivors had significantly prolonged mean latency of P300 (331.31±28.71 vs. 298.14±38.76 msec, P<0.001) and reaction time (439.51±119.86 vs. 380.11±79.94 msec, P=0.002) compared with in the control group. Abnormalities in the endogenous evoked potentials were observed in 36 patients (26.5%). The mean latency time was significantly longer in the treatment groups compared with in the control group (NY: 329.13±28.07 msec, P=0.001; pBFM: 332.97±23.97 msec, P<0.001; BFM95: 331.47±31.05 msec, P<0.001). The reaction time was equally prolonged in both groups. In comparisons between the studied groups and the control group the most significant prolongation was recorded in the NY group (461.8±140.3 vs. 380.1±78.04 msec, P=0.039). Significantly higher frequency of prolonged reaction time in non-irradiated patients that received BFM95 was also revealed (21.62 vs. 15.85%, P=0.007). In addition, radiotherapy significantly reduced the P300 wave amplitude (mean values: 10.395±5.727 vs. 12.739±6.508 mV, P=0.027). In conclusion, endogenous P300 event-related potentials may be a useful tool in screening of subclinical cognitive changes in ALL survivors.

Positions 299 and 302 of the GerAA subunit are important for function of the GerA spore germination receptor in Bacillus subtilis.

Bacillus subtilis, as a model spore-forming Gram-positive bacterium, has been extensively used for spore germination research. Within this field, nutrient-dependent germination with specific germinant receptors (GerA, responding to L-alanine or L-valine; GerB and GerK, acting together to start spore germination process in response to AGFK) has been the most studied. There are three different variants of the GerAA subunit (299T/302S, 299A/302P, 299A/302S) of the GerA germination receptor present in B. subtilis subs. subtilis laboratory strains. According to our research, the 299A/302P one, unlike the others, interferes with the spore's ability to germinate in L-alanine as assessed by the measurement of DPA release upon stimulation with the germinant. Multiple genetic manipulations described in this work followed by spore germination tests, together with secondary structure predictions led us to the following conclusions. First, position 302 of GerAA protein is crucial in terms of GerA germination receptor functionality; a proline residue at this position renders the GerA receptor non-functional, most probably due to a change in the protein secondary structure. Second, the 302P GerAA variant has most probably an impaired affinity to other components of GerA receptor. Together, these may explain the loss of GerA receptor's function. Analysis of the GerAA protein should get us closer to understanding the mechanism of GerA receptor function.

A system of vectors for Bacillus subtilis spore surface display.

BACKGROUND: Bacterial spores have been utilized as platforms for protein display. The best studied display systems are based on Bacillus subtilis spores in which several coat proteins have successfully been used as anchors for heterologous protein. Increasing knowledge about spore coat structure enables selection of new anchor proteins such as CotZ and CgeA. Here we describe a system of vectors for display of proteins on the surface of B. subtilis spores. RESULTS: We have designed and constructed a set of 16 vectors for ectopic integration which can be used for spore surface display of heterologous proteins. There is a selection of five coat proteins: CotB, CotC, CotG, CotZ and CgeA which can be used for construction of fusions. Three of these (CotB, CotC and CotG) enable obtaining N-terminal and C-terminal fusions and other two (CotZ and CgeA) are designed to produce C-terminal fusions only. All the vectors enable introduction of an additional peptide linker between anchor and displayed protein to enhance surface display. As a selection marker trophic genes are used. Additionally we describe an example application of presented vector system to display CagA protein of Helicobacter pylori in fusion with CgeA spore coat protein. CONCLUSIONS: Described system of vectors is a versatile tool for display of heterologous proteins on the surface of B. subtilis spores. Such recombinant spores can be further used as for example biocatalysts or antigen-carriers in vaccine formulations. The lack of antibiotic resistance genes in the system makes such spores an interesting option for applications in which a possible release to the environment can occur.