(RS)-N-[(4-Chloro­phen­yl)(phen­yl)­meth­yl]­formamide

The racemic title compound, C14H12ClNO, contains two mol­ecules in the asymmetric unit. The dihedral angles between the phenyl and benzene rings are 84.03 (15) and 83.92 (13)°. The crystal structure involves inter­molecular N—H⋯O, C—H⋯Cl and C—H⋯O hydrogen bonds, linking mol­ecules into layers parallel to the (100) plane

Grafting Miniature DNA Binding Proteins

AbstractMiniature proteins serve as leads for biological and medicinal applications by positioning all amino acids necessary for biomolecular recognition on a compact protein structure. Protein grafting was recently used to create miniature helical proteins with high DNA binding affinity and specificity

Entwicklung von Methoden zur Erfassung hydromorphologischer Strukturen aus Vermessungsdaten

Die flächenhafte Erfassung von Gewässerstrukturen ist für verschiedene hydromorphologische Fragestellungen von Bedeutung. Luftgestützte Fernerkundungsdaten bieten die Möglichkeit, eindeutige Strukturgrenzen anhand von messbaren Parametern zu bestimmen und somit den Aufwand zeit- und kostenintensiver Geländekartierungen zu reduzieren. In der vorliegenden Arbeit wurden die Potenziale hochaufgelöster Digitaler Geländemodelle sowie hochaufgelöster multispektraler Luftbilddaten für die Entwicklung von automatisierten Auswertungsverfahren zur objektiven und reproduzierbaren Strukturerfassung untersucht. Anhand eines Untersuchungsgebietes am Rhein nahe dem Naturschutzgebiet „Kühkopf-Knoblochsaue“ wurden verschiedene geometrische und radiometrische Parameter geprüft. Zur geometrischen Abgrenzung von Böschungen, Rinnen, Wällen und Senken wurde auf Basis von bestehenden Verfahren zur Bruchkantenextraktion eine Methodik entwickelt, um anhand des Parameters Krümmung Strukturabgrenzungen in Form von Ober- und Unterkanten zu erstellen. Die in der Literatur nicht eindeutig definierte Böschungsoberkante des Ufers wurde auf diese Weise ebenfalls objektiv verortet und die Lage- und Höhengenauigkeit anhand von terrestrisch vermessenen Oberkantenpunkten bestätigt. Die Uferböschung wurde in einem nachfolgenden Arbeitsschritt durch eine neigungsbasierte Methodik klassifiziert, wodurch eine Unterscheidung flacherer und steilerer Uferbereiche sowie die Detektion besonderer Uferformen, z.B. Stufenufern, möglich war. Die Erfassung von Auengewässern, Totholz, Bänken und ufernahen Sohlstrukturen kann mithilfe von Verfahren der computergestützten Bildanalyse und -klassifikation erfolgen, deren Potenziale in der vorliegenden Arbeit vorgestellt werden. Insgesamt kommen die Untersuchungen zu dem Ergebnis, dass die Entwicklung einer weitgehend automatisierten Gewässerstrukturkartierung möglich ist, Fachexpertise bei der fachgerechten Anwendung ist jedoch unabdingbar

Limited proteolysis of human histone deacetylase 1

BACKGROUND: Histone deacetylase (HDAC) proteins are associated with cell proliferation, differentiation, apoptosis, and cancer. Specifically, HDAC1 is linked with cell growth, a hallmark of cancer formation. HDAC1 is a phosphoprotein and phosphorylation at S421 and S423 promotes HDAC1 enzymatic activity and protein association. While single and double point mutants of HDAC1 at S421 and S423 appear functionally similar, the evidence suggests that HDAC1 is phosphorylated simultaneously at both S421 and S423 in vivo. Additional experiments are necessary to probe the role of double phosphorylation of HDAC1 at S421 and S423. RESULTS: To characterize HDAC1 phosphorylation at S421 and S423, limited proteolysis of HDAC1 was performed for the first time. HDAC1 degraded without production of discrete fragments. By performing concentration-dependent proteolysis, HDAC1 double point mutants with disrupted phosphorylation at S421 and S423 displayed different trypsin sensitivities compared to wild type HDAC1. Unexpectedly, HDAC1 single point mutants with disrupted phosphorylation at either S421 or S423 demonstrated protease sensitivity similar to the wild type HDAC1. CONCLUSION: Concentration-dependent proteolysis experiments provide evidence that phosphorylation of S421 and S423 individually contribute to HDAC1 function. In addition, the limited proteolysis experiments support a model where associated proteins promote HDAC1 enzymatic activity, reinforcing the importance of protein interactions in HDAC1 structure and function. Finally, because HDAC1 does not display distinct regions of protease sensitivity, the proteolysis studies suggest that HDAC1 comprises inter-related structural regions

Effect of axial tibial torque direction on ACL relative strain and strain rate in an in vitro simulated pivot landing

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring, and gastrocnemius muscle‐tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment, and internal or external tibial torque) was applied to the distal tibia while recording the 3D knee loads and tibofemoral kinematics. AM‐ACL relative strain was measured using a 3 mm DVRT. In this repeated measures experiment, the Wilcoxon signed‐rank test was used to test the null hypotheses with p  < 0.05 considered significant. The mean (±SD) peak AM‐ACL relative strains were 5.4 ± 3.7% and 3.1 ± 2.8% under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM‐ACL strain rates reached 254.4 ± 160.1%/s and 179.4 ± 109.9%/s, respectively. The hypotheses were supported in that the normalized mean peak AM‐ACL relative strain and strain rate were 70 and 42% greater under internal than under external tibial torque, respectively ( p  = 0.023, p  = 0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM‐ACL than does a corresponding external tibial torque. © 2011 Orthopaedic Research Society. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:528–534, 2012Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90222/1/21572_ftp.pd

Kinetic parameters for the binding of p-nitrophenyl [alpha]--mannopyranoside to concanavalin A

Binding of the chromogenic ligand p-nitrophenyl [alpha]--mannopyranoside to concanavalin A was studied in a stopped-flow spectrometer. Formation of the protein-ligand complex could be represented as a simple one-step process. No kinetic evidence could be obtained for a ligand-induced change in the conformation of concanavalin A, although the existence of such a conformational change was not excluded. The entire change in absorbance produced on ligand binding occurred in the monophasic process monitored in the stopped-flow spectrometer. The value of the apparent second-order rate constant (ka) for complex formation (ka = 54,000 s-1- at 25 [deg]C, pH 5.0, [Gamma]/2 0.5) was independent of the protein concentration when the protein was in the range of 233-831 [mu] in combining sites and in excess of the ligand. The apparent first-order rate constant (k-a) for dissociation of the complex was obtained from the rate constant for the decomposition of the complex upon the addition of excess methyl [alpha]--mannopyranoside (k-a = 6.2 s-1 at 25 [deg]C, pH 5.0, [Gamma]/2 0.5). The ratio ka/-a (0.9 x 104 -1) was in reasonable agreement with value of 1.1 +/- 0.1 x 104 -1 determined for the equilibrium constant for complex formation by ultraviolet difference spectrometry. Plots of ln(ka/T) and ln(ka/T) vs 1/T were linear (T is temperature) and were used to evaluate activation parameters. The enthalpies of activation for formation and dissociation of the complex are 9.5 +/- 0.3 and 16.8 +/- 0.2 kcal/mol, respectively. The unitary entropies of activation for formation and dissociation of the complex are 2.8 +/- 1.1 and 1.3 +/- 0.7 entropy units, respectively. These entropy changes are much less than those usually associated with substantial changes in the conformation of proteins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21838/1/0000241.pd

Hair-bearing human skin generated entirely from pluripotent stem cells

The skin is a multilayered organ, equipped with appendages (that is, follicles and glands), that is critical for regulating body temperature and the retention of bodily fluids, guarding against external stresses and mediating the sensation of touch and pain1,2. Reconstructing appendage-bearing skin in cultures and in bioengineered grafts is a biomedical challenge that has yet to be met3-9. Here we report an organoid culture system that generates complex skin from human pluripotent stem cells. We use stepwise modulation of the transforming growth factor β (TGFβ) and fibroblast growth factor (FGF) signalling pathways to co-induce cranial epithelial cells and neural crest cells within a spherical cell aggregate. During an incubation period of 4-5 months, we observe the emergence of a cyst-like skin organoid composed of stratified epidermis, fat-rich dermis and pigmented hair follicles that are equipped with sebaceous glands. A network of sensory neurons and Schwann cells form nerve-like bundles that target Merkel cells in organoid hair follicles, mimicking the neural circuitry associated with human touch. Single-cell RNA sequencing and direct comparison to fetal specimens suggest that the skin organoids are equivalent to the facial skin of human fetuses in the second trimester of development. Moreover, we show that skin organoids form planar hair-bearing skin when grafted onto nude mice. Together, our results demonstrate that nearly complete skin can self-assemble in vitro and be used to reconstitute skin in vivo. We anticipate that our skin organoids will provide a foundation for future studies of human skin development, disease modelling and reconstructive surgery