A CRISPR-Cas9 tool to explore the genetics of Bacillus subtilis phages

Here, we present pRH030, a new CRISPR-Cas9 tool for the genetic engineering of Bacillus phages and beyond. It is based on the Streptococcus pyogenes cas9 with its native constitutive promoter, tracrRNA, and a gRNA precursor. The constitutive expression of Cas9 was conducive to the inactivation of viral attackers and enhanced phage mutagenesis efficiency up to 100%. The gRNA precursor can be built up to an artificial CRISPR array with up to 5 spacers (target sequences) assembled from ordinary oligonucleotides and directly cloned into pRH030. Required time and resources remain comparable to a single gRNA cloning. These properties make pRH030 an attractive new system for the modification of Bacillus phages and qualify it for research beyond genetic construction.

Termination control of electronic phases in oxide thin films and interfaces: LaAlO3/SrTiO3(001)

A wealth of intriguing properties emerge in the seemingly simple system composed of the band insulators LaAlO(3) and SrTiO(3) such as a two-dimensional electron gas, superconductivity and magnetism. In this paper, we review the current insight obtained from first principles calculations on the mechanisms governing the behaviour of thin LaAlO(3) films on SrTiO(3)(001). In particular, we explore the strong dependence of the electronic properties on the surface and interface termination, the finite film thickness, lattice polarization and defects. A further aspect that is addressed is how the electronic behaviour and functionality can be tuned by an SrTiO(3) capping layer, adsorbates and metallic contacts. Lastly, we discuss recent reports on the coexistence of magnetism and superconductivity in this system for what they might imply about the electronic structure of this system.

Parallel electron-hole bilayer conductivity from electronic interface reconstruction

The perovskite SrTiO3-LaAlO3 structure has advanced to a model system to investigate the rich electronic phenomena arising at polar oxide interfaces. Using first principles calculations and transport measurements we demonstrate that an additional SrTiO3 capping layer prevents atomic reconstruction at the LaAlO3 surface and triggers the electronic reconstruction at a significantly lower LaAlO3 film thickness than for the uncapped systems. Combined theoretical and experimental evidence (from magnetotransport and ultraviolet photoelectron spectroscopy) suggests two spatially separated sheets with electron and hole carriers, that are as close as 1 nm.

A CdSe quantum dot based resonant cavity light-emitting diode showing single line emission up to 90 K

A II-VI wide-bandgap resonant cavity light-emitting diode is presented. The active region consists of CdSe quantum dots embedded in ZnSSe/MgS barriers, resulting in improved quantum efficiency at elevated temperatures. The resonant cavity is formed by a 14-period bottom distributed Bragg reflector and the semiconductor to air interface on top of the structure. Temperature dependent micro-electroluminescence measurements reveal emission of a single quantum dot up to 90 K. The turn-on voltages are 6 V at 4 K and 4 V at room temperature. These results are promising for the realization of green surface-emitting devices in general, and especially for an electrically driven prospective single photon source operating at room temperature.

Transcriptional regulation and biological significance of the insulin like growth factor II gene

The insulin like growth factors I and II are the most ubiquitous in the mammalian embryo. Moreover they play a pivotal role in the development and growth of tumours. The bioavailability of these growth factors is regulated on a transcriptional as well as on a posttranslational level. The expression of non-signalling receptors as well as binding proteins does further tune the local concentration of IGFs. This paper aims at reviewing how the transcription of the IGF genes is regulated. The biological significance of these control mechanisms will be discussed.

Ion-beam analysis of CuInSe2 solar cells deposited on polyimide foil

CuInSe(2) (CIS) solar cells deposited on polyimide foil by the Solarion company in a web-coater-based process using sputter and evaporation techniques were investigated in the ion beam laboratory LIPSION of the University of Leipzig by means of Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission (PIXE) using high-energy broad ion beams and microbeams. From these measurements the composition of the absorber and the lateral homogeneity and film thicknesses of the individual layers could be determined on the basis of some reasonable assumptions. For the first time, quantitative depth profiling of the individual elements was performed by microPIXE measurements on a beveled section prepared by ion-beam etching of a CIS solar cell. Within the CIS absorber layer no significant concentration-depth gradients were found for Cu, In, and Se, in contrast with results from secondary neutral mass spectrometry (SNMS) depth profiling, which was applied to the same samples for comparison. Furthermore, both PIXE and SNMS showed the presence of a remarkable amount of Cd from the CdS buffer layer in the underlying absorber.

A conserved structural element in horse and mouse IGF2 genes binds a methylation sensitive factor

The equine IGF2 gene has been cloned and characterised. It spans a 9 kb region, which is substantially less than the corresponding human gene. Three coding exons and three untranslated leader exons, all highly homologous to those in other species, were identified. Downstream of the polyadenylation site in exon 6, a dinucleotide repeat sequence was identified. Three putative promoters (P1-P3) were localised in the 5' region of the gene. RNase protection analysis revealed two active promoters in fetal tissues, P2 and P3, whereas P3 was the only promoter active in adult tissues. This represents a transcriptional pattern different from that in humans or rodents. A novel structural element, an inverted repeat, is predicted in the 3' region of the IGF2 gene. This repeat is conserved between species and located in a region which is differentially methylated in the human and mouse genes and might therefore be involved in the imprinting mechanism. The inverted repeat acquires a stem-loop structure in vitro with a hybrid A/B-DNA conformation in the stem area. Both in horse and mouse, a methylation-sensitive protein binds this structure with a strong requirement for the loop area. Furthermore, the protein might be developmentally regulated.

Liver lectin blocking with D-galactose to prevent hepatic metastases in colorectal carcinoma patients

Animal experiments in BALB/c-mice and in DBA/2-mice confirmed that lectin blockade with D-galactose containing receptor analogues can inhibit metastatic spread into the liver. The number of liver colonies of inoculated tumor cells was significantly reduced after D-galactose treatment as compared to animals of control group. Based on experimental investigations 193 colorectal carcinoma patients (UICC stages I-III) were enrolled in a prospectively randomized clinical trial. 93 patients were treated perioperatively with D-galactose- (treatment group: 1.5 g/kg body weight and per day) or D-glucose containing electrolyte infusions (control group: n = 100). Significant side effects were not observed. There were no cases of perioperative mortality. The overall complication rate was 7.3%. Since tumor stages were unequally distributed, analysis was performed in strata. Patients were observed for a total of 6237 months. Differences in overall survival and survival free of recurrence and hepatic metastases were negligible for stages I and II. For stage III carcinoma patients (n = 75) analysis of survival free of hepatic metastases revealed a shift to delayed events (i.e. hepatic metastases or death) after D-galactose treatment within 24 months following surgery. In patients with stage III carcinoma there was an indication for an overall benefit in survival after D-galactose treatment (p = 0.102).

FISH mapping of the IGF2 gene in horse and donkey-detection of homoeology with HSA11

Three genomic subclones derived from a phage clone containing the equine IGF2 gene were used to FISH map the gene on horse (ECA) and donkey (EAS) metaphase chromosomes. The gene mapped on ECA 12q13 band and is the first locus mapped to this horse chromosome. In donkey the gene mapped very terminal on the long arm of one small submetacentric chromosome that shows almost identical DAPI-banding pattern with ECA12. This is the first locus mapped in donkey genome. Cross species chromosome painting of equine metaphase chromosomes with human Chromosome (Chr) 11-specific probe showed homoeology of this human chromosome with ECA12 and ECA7. The novel ECA12 comparative painting results are thus in accordance with the localization of the equine IGF2 gene. Comparison of the hitherto known physical locations of IGF2 in different species, viz. human, cattle, sheep, horse, and donkey, shows that this gene tends to maintain a terminal location on the chromosome arm.

Cloning and sequencing of an equine insulin-like growth factor I cDNA and its expression in fetal and adult tissues

A cDNA for equine insulin-like growth factor I (IGF I) has been isolated by reverse transcriptase-polymerase chain reaction and subsequently sequenced. The sequenced fragment contained 465 bp including the coding regions for the signal peptide, the entire mature protein, and 4 amino acids into the E-peptide. Like its human counterpart, the mature equine IGF I peptide contains 70 amino acids and was 100% homologous between horse and man. The 49-amino-acid signal peptide had the threonine in position 26 of the human signal peptide substituted by isoleucine. The nucleotide homology across the entire clone was 96.3% between horse and man and 91.6% between horse and rat. The isolated cDNA hybridized to the same transcripts in fetal and adult tissues.

Insulin-like growth factor II in the horse: determination of a cDNA nucleotide sequence and expression in fetal and adult tissue

Horse cDNA for insulin-like growth factor II (IGF II) has been isolated. cDNA was synthesized from bulk mRNA and subsequently PCR-amplified and sequenced. Like its human counterpart, the mature horse IGF II peptide contains 67 amino acids with only two substitutions, isoleucine instead of valine in position 35 and asparagine instead of serine in position 36. The nucleotide homology was 92.1% between horse and human and 87.8% between horse and mouse. The isolated cDNA hybridized to multiple transcripts in fetal and adult tissues, thus confirming earlier reports on developmental expression of this gene in the horse.

[The significance of guided patient education on the value of metabolic control in a district center for diabetes mellitus]

In 409 diabetics, in most cases with an insufficient attitude to problems of metabolism, the state of knowledge was examined ay means of an interrogation action. This was followed by an intensifying of the instruction by group instruction. On an average 9 months after this a clearly improved knowledge was stated. At the same time metabolism had improved in 50.3% of the patients and deteriorated only in 7.9%.