Enhanced Population Control in a Synthetic Bacterial Consortium by Interconnected Carbon Cross-Feeding.

Engineered microbial consortia can provide several advantages over monocultures in terms of utilization of mixed substrates, resistance to perturbations, and division of labor in complex tasks. However, maintaining stability, reproducibility, and control over population levels in variable conditions can be challenging in multispecies cultures. In our study, we modeled and constructed a synthetic symbiotic consortium with a genetically encoded carbon cross-feeding system. The system is based on strains of Escherichia coli and Acinetobacter baylyi ADP1, both engineered to be incapable of growing on glucose on their own. In a culture supplemented with glucose as the sole carbon source, growth of the two strains is afforded by the exchange of gluconate and acetate, resulting in inherent control over carbon availability and population balance. We investigated the system robustness in terms of stability and population control under different inoculation ratios, substrate concentrations, and cultivation scales, both experimentally and by modeling. To illustrate how the system might facilitate division of genetic circuits among synthetic microbial consortia, a green fluorescent protein sensitive to pH and a slowly maturing red fluorescent protein were expressed in the consortium as measures of a circuit's susceptibility to external and internal variability, respectively. The symbiotic consortium maintained stable and linear growth and circuit performance regardless of the initial substrate concentration or inoculation ratio. The developed cross-feeding system provides simple and reliable means for population control without expression of non-native elements or external inducer addition, being potentially exploitable in consortia applications involving precisely defined cell tasks or division of labor.

Rectal cancer surgery : what's in a name?

The field of rectal cancer treatment is a dynamic and changing field, due to better understanding of the pathology and new medical treatment options, but perhaps mostly due to innovations in the surgical approach. Surgery is the cornerstone for rectal cancer treatment. Currently, Total Mesorectal Excision is the gold standard. After evolution towards laparoscopic TME, improving technology has led to the development of platforms that allow transanal TME and robotic TME. In addition, local excision can be performed safer and more accurately by means of Transanal Endoscopic Microsurgery (TEM), TransAnal Minimally Invasive Surgery or Endoscopic Submucosal Dissection (ESD), possibly avoiding TME. The aim of this review is to summarize the different surgical techniques and approaches for rectal cancer in function of tumor stage and describe the specifics of the technique.

Large deletions play a minor but essential role in congenital coagulation factor VII and X deficiencies.

UNLABELLED: Congenital factor VII (FVII) and factor X (FX) deficiencies belong to the group of rare bleeding disorders which may occur in separate or combined forms since both the F7 and F10 genes are located in close proximity on the distal long arm of chromosome 13 (13q34). We here present data of 192 consecutive index cases with FVII and/or FX deficiency. 10 novel and 53 recurrent sequence alterations were identified in the F7 gene and 5 novel as well as 11 recurrent in the F10 gene including one homozygous 4.35 kb deletion within F7 (c.64+430_131-6delinsTCGTAA) and three large heterozygous deletions involving both the F7 and F10 genes. One of the latter proved to be cytogenetically visible as a chromosome 13q34 deletion and associated with agenesis of the corpus callosum and psychomotor retardation. CONCLUSIONS: Large deletions play a minor but essential role in the mutational spectrum of the F7 and F10 genes. Copy number analyses (e. g. MLPA) should be considered if sequencing cannot clarify the underlying reason of an observed coagulopathy. Of note, in cases of combined FVII/FX deficiency, a deletion of the two contiguous genes might be part of a larger chromosomal rearrangement.

Cancer spectrum and frequency among children with Noonan, Costello, and cardio-facio-cutaneous syndromes.

BACKGROUND: Somatic mutations affecting components of the Ras-MAPK pathway are a common feature of cancer, whereas germline Ras pathway mutations cause developmental disorders including Noonan, Costello, and cardio-facio-cutaneous syndromes. These 'RASopathies' also represent cancer-prone syndromes, but the quantitative cancer risks remain unknown. METHODS: We investigated the occurrence of childhood cancer including benign and malignant tumours of the central nervous system in a group of 735 individuals with germline mutations in Ras signalling pathway genes by matching their information with the German Childhood Cancer Registry. RESULTS: We observed 12 cases of cancer in the entire RASopathy cohort vs 1.12 expected (based on German population-based incidence rates). This corresponds to a 10.5-fold increased risk of all childhood cancers combined (standardised incidence ratio (SIR)=10.5, 95% confidence interval=5.4-18.3). The specific cancers included juvenile myelomonocytic leukaemia=4; brain tumour=3; acute lymphoblastic leukaemia=2; rhabdomyosarcoma=2; and neuroblastoma=1. The childhood cancer SIR in Noonan syndrome patients was 8.1, whereas that for Costello syndrome patients was 42.4. CONCLUSIONS: These data comprise the first quantitative evidence documenting that the germline mutations in Ras signalling pathway genes are associated with increased risks of both childhood leukaemia and solid tumours.

[The histological confirmation of diffuse axonal injury in severe brain injury survivors]. / Der histologische Nachweis des diffusen axonalen Hirnschadens bei Überlebenden schwerer Schädel-Hirntraumen.

Diffuse axonal injury (DAI) plays a major role after traumatic brain injury (TBI). Its imaging is based on computed tomography (CT) or magnetic resonance imaging (MRI). However, DAI is a histological diagnosis. Histopathological findings on survival after TBI are very rare. Hence, it is unclear whether the neuroradiological findings are of clinical relevance. Cerebral specimens were taken in 24 patients with TBI requiring surgery. The presence of histopathological evidence for DAI was evaluated. Specimens were taken from an extracranial brain prolapse (n = 2) and from peripheral parts of a brain contusion (n = 22). Histological findings were correlated to the clinical course and the neurological status. A clinical follow-up was carried out 6 months after the surgery using the Glasgow Outcome Score (GOS). The study was approved by the local ethics committee. Specimens taken were temporal (n = 11), frontal (n = 8), parietal (n = 4) and cerebellar (n = 1). The incidence of DAI within these specimens was 30% (7 with DAI, 17 without DAI). DAI was verifiable up to 3 days after trauma. There was no correlation between DAI and Marshall classification in CT. The period of coma was longer in subjects with DAI. There was no difference in GOS in the case of a verified DAI. These results enforce the prognostic and neuroradiologic relevance of DAI. However, it is debatable whether the pathomorphologic findings in CT or MRI represent the histological findings of DAI. We suggest a multicentre study for further clarification.

Atomic imaging and direct phase retrieval using anomalous surface x-ray diffraction.

The application of multi-wavelength anomalous diffraction to thin films, interfaces and surface structures is presented. The method directly determines the amplitudes and phases of the complex surface structure factors from surface x-ray diffraction data, measured at three different energies around the absorption edge of one of the elements present in the film. Thereby, one is able to directly Fourier transform the data, which immediately provides meaningful and unambiguous electron-density distributions. These serve as a starting point for subsequent structural refinement. The robustness of the algorithm was evaluated on simulated data as a proof of principle. The experimental limitations and their effect on the method will be discussed as well as stability tests for the algorithm, such as the positions of the anomalous scatterers and the interfacial roughness. It will be shown that the method can be applied to real structures. The algorithm was tested on real data from a thin film of SrTiO(3) grown on NdGaO(3)(110).

CHD7 mutations causing CHARGE syndrome are predominantly of paternal origin.

CHARGE (coloboma, heart defects, atresia of the choanae, retarded growth and development, genital hypoplasia, ear anomalies and deafness) syndrome is a congenital malformation syndrome caused by mutations in the CHD7 gene in approximately 2/3 of cases. In the vast majority of cases, CHARGE syndrome is sporadic. There are only a few reports of parent-to-child transmission and somatic or gonadal mosaicism. To determine the parental origin of CHD7 mutations in sporadic CHARGE syndrome, we screened 30 families for informative exonic or intronic polymorphisms located near the detected CHD7 mutation. An informative polymorphism could be identified in 13 out of 30 families. Linkage analysis was performed between the CHD7 mutation and the polymorphism in the child. In 12 out of 13 families, the mutation affected the paternal allele (92.3%). In our cohort, the mean paternal age at birth was 32.92 years. Comparing the age of fathers of an affected CHARGE patient with the paternal age of the German population in general, we could not observe any paternal age effect. Taken together, we show in this study that de novo CHD7 mutations occur predominantly in the male germ line.

Electrostriction at the LaAlO3/SrTiO3 interface.

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar LaAlO(3) layer grown on SrTiO(3) substrates. From the structural data, a complete screening of the LaAlO(3) dipole field is observed for film thicknesses between 6 and 20 uc. For thinner films, an expansion of the c axis of 2% matching the theoretical predictions for an electrostrictive effect is observed experimentally.

Evolution of the interfacial structure of LaAlO3 on SrTiO3.

The evolution of the atomic structure of LaAlO_{3} grown on SrTiO_{3} was investigated using surface x-ray diffraction in conjunction with model-independent, phase-retrieval algorithms between two and five monolayers film thickness. A depolarizing buckling is observed between cation and oxygen positions in response to the electric field of polar LaAlO_{3}, which decreases with increasing film thickness. We explain this in terms of competition between elastic strain energy, electrostatic energy, and electronic reconstructions. Based on these structures, the threshold for formation of a two-dimensional electron system at a film thickness of 4 monolayers is quantitatively explained. The findings are also qualitatively reproduced by density-functional-theory calculations.

Stenosis of a colorectal anastomosis solved by transanal endoscopic microsurgery combined with laparoscopy.

OBJECTIVE: The objective of this case report is to present a minimally invasive technique for solving an anastomotic colorectal stenosis using Transanal Endoscopic Microsurgery (T.E.M.) in combination with laparoscopy. SUMMARY: Often a re-intervention is indicated for the resolution of an anastomotic (sub-) obstruction. This re-intervention is associated with the morbidity and mortality of a laparotomy and a prolonged hospital stay. In the case here presented, a 68-year-old man underwent a laparoscopic rectosigmoid resection for a rectal adenocarcinoma. An end-to-end circular stapled colorectal anastomosis was performed. At first without any postoperative problems, the patient presented with a stenosis of the anastomosis 6 months postoperatively. This stenosis did not result in a total obstruction but was sufficiently advanced to cause faecal impaction and discomfort, which was confirmed using a retrograde gastrografine bowel study. Colonoscopic dilatations were insufficient and after several days the patient experienced a recurrence of the original stenosis. A minimally invasive re-intervention with T.E.M. was performed in combination with laparoscopy to solve the stenosis. To our knowledge, this technique has not yet been described. CONCLUSION: In this paper we describe a possible minimally invasive technique to avoid laparotomy after colorectal or colo-anal anastomotic stenosis. Both the duration of the hospital stay and patient morbidity can be reduced in this way.

Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures with hard x-ray photoelectron spectroscopy.

The conducting interface of LaAlO3/SrTiO3 heterostructures has been studied by hard x-ray photoelectron spectroscopy. From the Ti 2p signal and its angle dependence we derive that the thickness of the electron gas is much smaller than the probing depth of 4 nm and that the carrier densities vary with increasing number of LaAlO3 overlayers. Our results point to an electronic reconstruction in the LaAlO3 overlayer as the driving mechanism for the conducting interface and corroborate the recent interpretation of the superconducting ground state as being of the Berezinskii-Kosterlitz-Thouless type.

Proven germline mosaicism in a father of two children with CHARGE syndrome.

CHARGE syndrome is an autosomal dominant malformation syndrome caused by mutations in the CHD7 gene. The majority of cases are sporadic and only few familial cases have been reported. In these families, mosaicism in one parent, as well as parent- to-child transmission of a CHD7 mutation, has been described. In some further cases, germline mosaicism has been suggested. Here, we report the first case in which germline mosaicism could be demonstrated in a father of two affected children with CHARGE syndrome. The truncating mutation c.7302dupA in exon 34 of the CHD7 gene was found in both affected children but was not detected in parental lymphocytes. However, in DNA extracted from the father's spermatozoa, the c.7302dupA mutation could be identified. Furthermore, mutation analysis of DNA isolated from 59 single spermatozoa revealed that the c.7302dupA mutation occurs in 16 spermatozoa, confirming germline mosaicism in the father of the affected children. This result has a high impact for genetic counselling of the family and for their recurrence risk in further pregnancies.

Graphene on Ru(0001): a 25 x 25 supercell.

The structure of a single layer of graphene on Ru(0001) has been studied using surface x-ray diffraction. A surprising superstructure containing 1250 carbon atoms has been determined, whereby 25 x 25 graphene unit cells lie on 23 x 23 unit cells of Ru. Each supercell contains 2 x 2 crystallographically inequivalent subcells caused by corrugation. Strong intensity oscillations in the superstructure rods demonstrate that the Ru substrate is also significantly corrugated down to several monolayers and that the bonding between graphene and Ru is strong and cannot be caused by van der Waals bonds. Charge transfer from the Ru substrate to the graphene expands and weakens the C-C bonds, which helps accommodate the in-plane tensile stress. The elucidation of this superstructure provides important information in the potential application of graphene as a template for nanocluster arrays.

Anastomotic leakage of a colorectal anastomosis treated by transanal endoscopic microsurgery.

OBJECTIVE: To report a minimal invasive technique for repairing an anastomotic leakage with Transanal Endoscopic Microsurgery (T.E.M.) without creating a protective ostomy. SUMMARY: There are a large number of techniques for the management of anastomotic leakage after colorectal surgery. Depending on the size and location of the disruption, a protective ileostomy, a permanent colostomy or even reintervention for drainage or closure of the leak may be indicated. In most cases the patient faces the morbidity associated with a new intervention, a prolonged hospital stay and a future operation for closure of the stoma. In the present case a 56-year-old man underwent a laparoscopic rectosigmoid resection after two episodes of diverticulitis in six months. An end-to-end circular stapled anastomosis was constructed. Unfortunately 8-days postoperatively an anastomotic leak occurred. Attempts to close the tear non-surgically with colonoscopy and clipping failed. A minimally invasive reintervention with transanal endoscopic microsurgery (T.E.M.) was performed without creation of an ileostomy. One week postoperatively a gastrografin bowel study showed no leakage. To our knowledge, this technique has not yet been reported without the simultaneous construction of a stoma. CONCLUSION: We describe a possible minimally invasive technique to avoid laparotomy and/or the creation of a derivative stoma in the management of anastomotic leakage. Hospital stay is not significantly prolonged, future reïntervention for closure of stoma is avoided and sphincter function is preserved.

[Cancer screening for women is less frequently visited in regions with lower household income--analysis of data from health insurances in Bavaria]. / Die Krebsfrüherkennungsuntersuchung für Frauen wird in Regionen mit niedrigerem Haushaltseinkommen seltener in Anspruch genommen--Analyse von Daten der Kassenärztlichen Vereinigung Bayerns.

AIM OF THE STUDY: Differences in health care in Germany have rarely been analysed. Recent research, however, indicates that subjects of the lower social class participate in cancer screening less frequently. METHODS: Participation in screening for cervical cancer among women older than 20 years has been analysed using billing information of the KVB (Kassenärztlichen Vereinigung Bayern) for the period from 2002-2005. Women were assigned to one of the 96 Bavarian districts based on their postal code. The following variables were used: Participation rate in cervical cancer screening; age; average household income; gynaecologists per 10,000 women. Multivariate analyses were based on age-stratified linear regressions. RESULTS: There are considerable regional differences in participation in screening for cancer among older women. Participation rates are lower in districts with lower average household income. The correlation between participation rates and average household income shows an almost linear dependence on the level of districts. This association could not be explained by the variable "gynaecologists per 10,000 women". CONCLUSION: In order to provide social equality in health care, regional differences in cancer screening participation should be targeted. This is especially important in districts with lower average household incomes.

Compound heterozygosity in the SPG4 gene causes hereditary spastic paraplegia.

The SPG4 gene is frequently mutated in autosomal dominant form of hereditary spastic paraplegia (HSP). We report that the compound heterozygous sequence variants S44L, a known polymorphism, and c.1687G>A, a novel mutation in SPG4 cause a severe form of HSP in a patient. The family members carrying solely c.1687G>A mutation are asymptomatic for HSP. The reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that the c.1687G>A mutation is a splice site mutation and causes skipping of the exon 15 of spastin. Furthermore, quantification of RT-PCR products by sequencing and quantification of allele-specific expression by pyrosequencing assay revealed that c.1687G>A is a leaky or hypomorphic splice site mutation. At the protein level, c.1687G>A mutation in SPG4 leads to E563K substitution. In ex vivo study, about 10% of cells expressing E563K mutant spastin showed filamentous expression pattern, suggesting a hypomorphic effect at the protein level. Collectively, our results suggest that S44L in association with c.1687G>A (E563K) drops the functional level of spastin below a threshold limit sufficient to manifest HSP.

Conducting interfaces between polar and non-polar insulating perovskites.

Two-dimensional electron gases in semiconductors have found use in applications such as optoelectronics, high-power radio-frequency and magnetoelectronic devices. The ability to grow heterostructures of oxides exhibiting similar effects is a significant step towards the fabrication of all-oxide devices. Here, we give an overview of recent studies of two-dimensional electron gases formed at the interface between polar and non-polar perovskites. We discuss the proposed explanations of the origin of the conductivity and properties of the ground state.

Structural basis for the conducting interface between LaAlO3 and SrTiO3.

The complete atomic structure of a five-monolayer film of LaAlO3 on SrTiO3 has been determined for the first time by surface x-ray diffraction in conjunction with the coherent Bragg rod analysis phase-retrieval method and further structural refinement. Cationic mixing at the interface results in dilatory distortions and the formation of metallic La(1-x)SrxTiO3. By invoking electrostatic potential minimization, the ratio of Ti{4+}/Ti{3+} across the interface was determined, from which the lattice dilation could be quantitatively explained using ionic radii considerations. The correctness of this model is supported by density functional theory calculations. Thus, the formation of a quasi-two-dimensional electron gas in this system is explained, based on structural considerations.

Tumors of low malignant potential arising in the fallopian tube: case reports.

BACKGROUND: There is a paucity of information regarding fallopian tube tumors of low malignant potential (LMP) in the literature. CASE: We present two cases representing alternative management options of low LMP of the fallopian tube. CONCLUSION: Although low malignant potential tumors of the ovary are relatively common, there are few reported cases of tumors of LMP originating in the fallopian tube. Treatment has been extrapolated from tumors of LMP of the ovary, and conservative fertility-sparing surgery and complete staging procedure remains controversial. We urge continued reporting of these fallopian tube tumors of LMP to enhance understanding of these rare tumors and to develop a more cohesive treatment plan.

Functional and immunophenotypic characteristics of isolated CD105(+) and fibroblast(+) stromal cells from AML: implications for their plasticity along endothelial lineage.

BACKGROUND: In vitro cultures of BM cells from newly diagnosed patients with AML displayed a defective BM stromal compartment, with a reduced number of fibroblast-colony-forming unit (CFU-F: 1 +/- 1.25 SD) and a decreased proliferative ability. The purposes of our study were: 1). to select BM mesenchymal stem cells (MSC) and BM-derived stromal cells (BMDSCs) from AML patients at diagnosis and from healthy subjects, using an immunomagnetic system and either anti-CD105 or anti-fibroblast MAbs; 2). to study the immunophenotypic and functional properties of freshly isolated and cultured mesenchymal cells; 3). to test the in vitro plasticity of the selected cells to differentiate towards an endothelial phenotype. METHODS: Fresh mononuclear cells obtained from BM of 20 patients newly diagnosed with AML and from eight healthy subjects were selected by using anti-fibroblast and anti-CD105 MAbs. Freshly isolated cells were analyzed, characterized by flow cytometry using a wide panel of MAbs and seeded in long-term culture medium to assess CFU-F formation. The level of confluence after 30 days and functional capacity in a long-term colony-forming cell culture (LTC-CFC) were tested. Furthermore, the cultured selected cell populations were assayed for their ability to differentiate into an endothelial-like cell phenotype with the addition of vascular endothelial growth factor (VEFG) and endothelial cell growth supplement (ECGS). RESULTS: In normal subjects the selection produced an increase of the CFU-F number of 2.6-fold with anti-fibroblast MAb and 2.7-fold with the anti-CD105 MAb. Anti-fibroblast and anti-CD105 MAb selection from AML BM cells resulted in a statistically significant greater count of CFU-F that was respectively 10.6-fold (P = 0.04) and 14.4-fold (P = 0.00001) higher in comparison with the unselected AML samples. Interestingly, in 80% of AML samples immunoselection was also able to restore the capacity of the CFU-F to proliferate and form confluent stromal layers. The isolation of those layers sustained the proliferation and differentiation of hematopoietic stem cells in the LTC-CFC. The phenotypic profile of cultured BMDSCs was different from that of the freshly isolated cells, and changed in relation to the culture conditions: CD105+ selected cells cultured with VEGF and ECGS expressed endothelial markers, a finding that suggests that this cell subpopulation may have the potential to differentiate toward an endothelial-like phenotype. DISCUSSION: We report that immunomagnetic selection represents a valid tool for the selection of BM mesenchymal cells in samples obtained from both healthy subjects and patients with AML. This technique was able to rescue two functional and immunophenotypic compartments related to two different selected populations. In particular, the CD105+ cells isolated in AML displayed, after stimulation with VEGF and ECGS, the ability to change towards an endothelial-like cell phenotype, thus revealing an unexpected plasticity. Both CD105+ and fibroblast+ cells once successfully isolated might represent sources of mesenchymal cells populations useful for in vitro investigations and, above all, as therapeutic devices.