Biomineralization of gold in biofilms of Cupriavidus metallidurans

Cupriavidus metallidurans, a bacterium capable of reductively precipitating toxic, aqueous gold(I/III)-complexes, dominates biofilm communities on gold (Au) grains from Australia. To examine the importance of C. metallidurans biofilms in secondary Au formation, we assessed the biomineralization potential of biofilms growing in quartz-sand-packed columns to periodic amendment with Au(I)-thiosulfate. In these experiments, >99 wt % of Au, was retained compared to <30 wt % in sterilized and abiotic controls. Biomineralization of Au occurred in the presence of viable biofilms via the formation of intra- and extra-cellular spherical nanoparticles, which aggregated into spheroidal and framboidal microparticles of up to 2 μm in diameter. Aggregates of Au formed around cells, eventually encapsulating and ultimately replacing them. These particles were morphologically analogous to Au-particles commonly observed on natural Au grains. Bacterial cells were connected via exopolymer or nanowires to μm-sized, extracellular Au-aggregates, which would intuitively improve the flow of electrons through the biofilm. This study demonstrates the importance of C. metallidurans biofilms for the detoxification of Au-complexes and demonstrates a central role for bacterial biomineralization in the formation of highly pure Au in surface environments.

[Tumor microenvironment in gastrointestinal tumors]

The growing potential of modern molecular analysis tools has led to a sharp increase in the understanding of the molecular dimension of pathological processes and, consequently, to a growing influence of pathological diagnoses on the selection of therapeutic approaches. Molecular analysis tools have also led to the understanding that groups of tumors hitherto considered to belong to a single, homogeneous disease entity should rather be divided into subgroups with specific molecular attributes, growth behavior patterns and, consequently, different prognostic characteristics and therapeutic needs. A major factor contributing to the differentiation of these subgroups is the composition of the tumor microenvironment (ME), a compartment that is involved in the control of critical carcinogenetic processes such as angiogenesis and invasive growth. Consequently, the investigation of the ME promises to be a most auspicious field of research for pathologists and there is hope that the increased understanding of the interaction between neoplastic cells and the ME will lead to improved diagnostic tools and novel therapeutic approaches for the treatment of cancer patients.

A human recombinant autoantibody-based immunotoxin specific for the fetal acetylcholine receptor inhibits rhabdomyosarcoma growth in vitro and in a murine transplantation model

Rhabdomyosarcoma (RMS) is the most common malignant soft tissue tumor in children and is highly resistant to all forms of treatment currently available once metastasis or relapse has commenced. As it has recently been determined that the acetylcholine receptor (AChR) gamma-subunit, which defines the fetal AChR (fAChR) isoform, is almost exclusively expressed in RMS post partum, we recombinantly fused a single chain variable fragment (scFv) derived from a fully human anti-fAChR Fab-fragment to Pseudomonas exotoxin A to generate an anti-fAChR immunotoxin (scFv35-ETA). While scFv35-ETA had no damaging effect on fAChR-negative control cell lines, it killed human embryonic and alveolar RMS cell lines in vitro and delayed RMS development in a murine transplantation model. These results indicate that scFv35-ETA may be a valuable new therapeutic tool as well as a relevant step towards the development of a fully human immunotoxin directed against RMS. Moreover, as approximately 20% of metastatic malignant melanomas (MMs) display rhabdoid features including the expression of fAChR, the immunotoxin we developed may also prove to be of significant use in the treatment of these more common and most often fatal neoplasms.

A synchrotron X-ray diffraction analysis of near-stoichiometric LiNbO3

Single-crystal diffraction data was collected at 120 and 294 K for an approximately spherical LiNbO3 crystal, 16 μm in diameter, using focused λ=0.7516 (1) Å wavelength synchrotron X-radiation and a fast avalanche photodiode (APD) detector. Extinction was significantly less than that recorded for previous single-crystal X-ray diffraction experiments. Anharmonic atomic displacements of Nb and Li were refined using a Gram-Charlier expansion to the fourth order. There was no significant change in the topography of the difference electron density (Δρ) map after anharmonic refinement. An accumulation of electrons present at the vacant site in the 294 K Δρ map was not evident in the 120 K Δρ map, indicating a migration of Li atoms to the vacant site as the temperature increased. The orientation of the electron density around Nb flipped by 90° going from 120 to 294 K.

Selection of reference genes for quantitative real-time PCR analysis in canine mammary tumors using the GeNorm algorithm

Eleven reference genes (18s ribosomal ribonucleic acid [RNA], 28s ribosomal RNA, ubiquitin, beta-actin, glycerine aldehyde dehydrogenase, ATP-synthase subunit 5B, hydroxymethyl-bilane synthase, hypoxanthine-phosphoribosyl transferase, ribosomal protein L32, tryptophan 5-monooxygenase activation protein (zeta polypeptide), and TATA-Box binding protein) were analyzed in use as references for gene expression profiling experiments using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in canine mammary tumors. The transcription level of the candidates was measured in 22 histologically characterized excised tumor specimens from mammary gland tissue and 22 samples of non-neoplastic mammary tissue samples from the same individuals. Results were used to rank candidate reference genes using the GeNorm tool. It was determined that in samples of canine mammary gland tissue, a combination of hypoxanthine-phosphoribosyl transferase, ATP-synthase subunit 5B, ribosomal protein L32 and ubiquitin yields stable reference gene expression levels, whereas the use of glycerin aldehyde dehydrogenase or ribosomal RNA is unsuitable for normalization of qRT-PCR results in this tissue type.

[Prevalence and association of porcine circovirus type 2 (PCV2), porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus (PRRSV) in aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets]

Porcine circovirus type 2 (PCV2) seems to cause reproductive failure in sows not only in experimental studies. A retrospective study was made with a total of 252 aborted fetuses, mummified fetuses, stillborn and nonviable neonatal piglets to determine the presence of PCV2, porcine parvovirus (PPV) and porcine respiratory and reproductive syndrome virus (PRRSV) by PCR. PCV2 was found in all stages of gestation in 27.1 percent of samples examined. A statistically significant association could be shown between the detection of PCV2 and PRRSV. However, no significant association was seen between the detection of PCV2 and PPV and between PPV and PRRSV.

Synchrotron X-ray study of Er3Al5O12 and Yb3Al5O12 garnets

Structure factors for Er(3)Al(5)O(12) and Yb(3)Al(5)O(12) garnets were measured using focused synchrotron X-radiation, with lambda = 0.7500 (2) and 0.7000 (2) A, respectively. The difference electron density maps for Er(3)Al(5)O(12) and Yb(3)Al(5)O(12) were similar, as expected. This was attributed to the 4f electrons being shielded, which reduces their effectiveness in chemical bonding and the relative position of the rare-earth atoms in the periodic table. The symmetry of the difference electron density around the rare-earth atoms was found to reflect that of the cation geometry, emphasizing the importance of second nearest-neighbor interactions. This is consistent with the view that oxide-type structures may be regarded as a packed array of cations with anions in the interstices.