Advanced characterization of natural biofilm on nanofiber scaffold.

Nanofiber scaffolds provide numerous advantages over common carriers engineered for microorganisms. The most important advantage is an increased speed of primary surface colonization (up to four times faster), which shortens the time required for the areal biofilm formation and optimum performance of attached microorganisms (higher efficiency of biological activity of up to twice as fast). Image analysis predicts early formation of biofilm even in beginning stages; analysis of biofilm reveals the different structures of bacterial colonies on both scaffolds (higher porosity, size, and number of bacterial colonies on nanofiber's surface). The image analysis correlates well with determinations of dry matter (linear correlation of 0.96) and proteins (linear correlation of 0.89).

An accurate method for determining the helical repeat of DNA in solution reveals differences to the crystal structures of two B-DNA decamers.

Many DNA sequences have been studied by X-ray crystallography with the goal of deciphering a sequence-structure code. We have determined the helical repeats of two B-type DNA decamers in solution employing an electrophoretic method based on phasing of bent segments. The decamers contain recognition sites for the dcm methyltransferase and for the restriction nuclease NarI with a mutational hotspot. Their helical repeats are 10.59(+/- 0.05) bp and 10.52(+/- 0.03) bp, respectively, whereas crystallographic analysis yielded 10.0 bp in the solid state. This difference is greater than that for the transition between B- and A-type DNA in solution. Thus, reliable information about the polymorphism of DNA in solution must be based on both X-ray and solution data. We describe a generally applicable approach to accurately determine helical repeats of small DNA duplexes in solution.

Biodegradability of ethylenediamine-based complexing agents.

Biological degradability of ethylenediamine derivatives depends on the type and number of substituents. The susceptibility to biodegradation decreases in the sequence of substituents -COCH3, -CH3, -C2H5, -CH2CH2OH, -CH2COOH and with polysubstitution. The biodegradability depends also on the kind and number of nitrogen atoms. Complexing agents with a single-nitrogen atom in the molecule (e.g. NTA) succumb relatively readily to biodegradation whereas, compounds with two or more tertiary amino groups are biologically highly stable and do not undergo biodegradation even in experiments with activated sludge adapted at an age of up to 30 days (EDTA, DTPA, PDTA, HEDTA). A lowering of the degree of substitution brings about an increased susceptibility to biodegradation. This holds, e.g., for replacement of tertiary amino groups with secondary ones; thus the symmetrically disubstituted ethylenediamine-N,N'-diacetic acid (EDDA) possesses still sufficient complexing ability while belonging already to the group of potentially degradable substances.

Joint analysis of the NACP-REP1 marker within the alpha synuclein gene concludes association with alcohol dependence.

Various studies have linked alcohol dependence phenotypes to chromosome 4. One candidate gene is NACP (non-amyloid component of plaques), coding for alpha synuclein. Recently, it has been shown that alpha synuclein mRNA is increased in alcohol-dependent patients within withdrawal state. This increase is significantly associated with craving, especially obsessive craving. On the basis of these observations, the present study analysed two polymorphic repeats within the NACP gene. We found highly significant longer alleles of NACP-REP1 in alcohol-dependent patients compared with healthy controls (Kruskal-Wallis test, chi(2)=99.5; df=3, P<0.001). In addition, these lengths significantly correlate with levels of expressed alpha synuclein mRNA (chi(2)=8.83; df=2, P=0.012). The present results point to a novel approach for a genetic determination of craving, a key factor in the genesis and maintenance not only of alcoholism but also of addiction in general.

Thermodynamic analysis of tetracycline-mediated induction of Tet repressor by a quantitative methylation protection assay.

We describe a method for quantitative detection and thermodynamic interpretation of tetracycline (tc)-mediated induction of the Tn10 encoded Tet repressor (TetR). Binding of dimeric TetR to the tet operator (tetO) was quantitated by protection of DNA from methylation as a function of te concentration. A thermodynamic scheme covering all single reactions relevant for TetR induction was used to interpret the data. The equilibrium association constants of the TetR-[Mg-tc]+ and TetR-[Mg-tc]2+ complexes to tetO were determined at different NaCl and TetR concentrations. Variation of total TetR concentration from 0.2 to 1.1 x 10(-7) M yielded identical results. A strong salt dependency of TetR-tetO binding was verified between 2.5 and 100 mM NaCl, whereas [Mg-tc]+ binding to TetR is independent of the ionic strength. The TetR-tetO binding constant drops 10(2)- to 10(3)-fold upon binding of the first and further 10(4)- to 10(7)-fold by binding of the second [Mg-tc]+. This apparent cooperativity of tc-mediated induction indicates that each [Mg-tc]+ interacts with both TetR monomers.

DNA analysis of fingernail debris using different multiplex systems: a case report.

A 55-year-old male nurse was accused of having introduced his fingers by force into the anus of a 20-year-old female patient. Debris from the fingernails of the suspect recovered 2 days after the incident was analysed with the VNTR locus D1S80, the triplex PCR system AmpFlSTR Blue kit, the AmpFlSTR Profiler kit and the pentaplex system genRES MPX. The D1S80 singleplex reaction revealed indications of DNA from the victim in the fingernail debris of the left hand. Using the AmpFlSTR Blue kit and AmpFlSTR Profiler, DNA alleles of the victim were found at four additional loci, while allelic drop-out was observed at five other loci. Only the pentaplex kit genRES MPX revealed alleles at all loci which could be assigned to the victim. Calculation of likelihood ratios resulted in a value of 1.4 x 10(5) using the combination of the multiplex systems AmpF1STR Blue kit and AmpFlSTR Profiler and 2.8 x 10(8) for the genRES MPX kit. This case demonstrates the high sensitivity of the new genRES MPX kit and that DNA profiling of fingernail debris is possible despite a time lapse of 2 days between the incident and recovery of the evidential material.

Matrix effects suggest an important influence of DNA-polyacrylamide interactions on the electrophoretic mobility of DNA.

The electrophoretic mobilities of 34 DNA fragments with a varied phasing of two A-tract bends have been determined in different polyacrylamide gels. They are perfectly described by a cosine function. A systematic variation of the polyacrylamide gel matrix revealed that not only the absolute electrophoretic mobilities of these distance variants, but also their amplitudes and the positions of their extrema, depend on the polyacrylamide content. The displacement of the extrema with increasing polyacrylamide content is attributed to gel-induced unwinding of the DNA. None of these matrix effects can be explained by the change of the pore sizes, which is generally regarded as the central parameter determining electrophoretic mobility of DNA in gels. Instead, we hypothesize an interaction between the electrophoresed DNA and the polyacrylamide matrix and discuss a new qualitative model for electrophoresis of DNA in polyacrylamide gels which accounts for these observations.

A new pentaplex PCR system for forensic casework analysis.

In 1998 the Federal Criminal Police Office of Germany (BKA) established a central genetic database of offenders and suspects to facilitate comparisons with biological samples from future criminal offences. The five obligatory short tandem repeat (STR) loci in this database (TH01, SE33, vWA, FGA and D21S11) were co-amplified in a new PCR pentaplex analysing system together with the sex-specific locus amelogenin. Due to overlapping fragment sizes, amplification products were fluorescent dye-labelled with different colours, separated by electrophoresis and detected directly using the ABI PRISM 310 Genetic Analyzer. Reproducible and reliable results were obtained from as low as 125 pg template DNA, indicating high specificity and sensitivity of the assay. Environmental studies and enzymatic digest with DNase I revealed an excellent stability of the pentaplex system with typeable results even in cases of partially degraded DNA. Complete and reproducible DNA typing was possible in blood-stain mixtures with the minor component as low as 10%. Mean stutter peak intensities were analysed for all loci and ranged from 2.7 +/- 0.8% (TH01) to 10.6 +/- 1.6% (vWA) of the main signal intensity. Allele frequencies were determined in a North Bavarian population sample (n = 121). The combination of five systems resulted in a mean exclusion chance of 99.86% and a power of discrimination of 99.999996%. No deviation from Hardy-Weinberg equilibrium could be found.

[Acupuncture for the treatment of pain-a prospective study.]. / Schmerztherapie mit Akupunktureine prospektive Studie.

Acupuncture is increasingly being used in Western medicine. In the present study the effect of acupuncture treatment was examined in 60 patients with chronic pain. The long-term success after 6 months was evaluated in 45 patients. Calculated on the basis of an index of the frequency of pain, its duration and intensity, a global success rate of 64% was found directly after the therapy and of 69% 6 months later. Furthermore, we examined to what extent the success of the therapy was dependent on several variables. It appeared that the consumption of analgesics could be reduced significantly in patients in whom the treatment was successful. All patients had been treated before by several methods. Because of the small number of side-effects and the patients' high degree of acceptance as well as the success of the treatment, we consider acupuncture an effective method in the treatment of chronic pain.

Validation of the multiplex kit genRESMPX-2 for forensic casework analysis.

Validation studies were carried out using the commercially available PCR multiplex system genRESMPX-2. In addition to amelogenin, this system comprises the complete set of eight STR systems which are components of the German DNA database established in 1998 by the Federal Criminal Office of Germany (BKA). The minimum amount of template DNA which gave a complete DNA pattern ranged between 100 pg and 200 pg. Mixed samples could clearly be assigned from ratios between 1:5 (ACTBP2) and 1:20 (VWA, FGA). Experimental investigations with different forensic materials, environmental studies, reproducibility and precision data as well as practical casework analysis revealed that the genRESMPX-2 kit can be regarded as a sensitive, reliable and robust multiplex system even in the case of samples containing limited amounts or degraded DNA.

The effect of parenteral alimentation fluid, undiluted with saline or fresh sera, on the growth of Candida albicans in vitro at 37 degrees C.

Parenteral alimentation is often complicated by Candida albicans infection which may be fatal. This study investigated the effect of alimentation fluid (Aminosol) on C. albicans' growth in vitro. It was found that concentrated Aminosol (1400 millisomoles) maintained C. albicans in a viable state but inhibited replication. Dilution of alimentation fluid to physiological concentrations (300 milliosmoles) with either saline or aged pooled normal sera promoted in vitro growth of C. albicans which was equivalent to that obtained in BHI broth and was slightly less than that obtained in Sabouraud's broth. The effects of fresh sera with full complement activity were also investigated. In fresh sera appropriately diluted with physiological saline, some clumping of the yeasts was observed and all formed germ tubes. Growth as defined by budding or the formation of hyphae was inhibited. When Aminosol was diluted to 300 milliosomoles with fresh sera, all yeasts were noted to be in clumps with germ tubes as well as continually growing hyphae. Growth was approximately equal to that seen in Aminosol similarly diluted with saline.