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Canonical G‐quadruplexes can adopt a variety of different topologies depending on the arrangement of propeller, lateral, or diagonal loops connecting the four G‐columns. A novel intramolecular G‐quadruplex structure is derived through inversion of the last G‐tract of a three‐layered parallel fold, associated with the transition of a single propeller into a lateral loop. The resulting (3+1) hybrid fold features three syn⋅anti⋅anti⋅anti G‐tetrads with a 3’‐terminal all‐syn G‐column. Although the ability of forming a duplex stem‐loop between G‐tracts seems beneficial for a propeller‐to‐lateral loop rearrangement, unmodified G‐rich sequences resist folding into the new (3+1) topology. However, refolding can be driven by the incorporation of syn‐favoring guanosine analogues into positions of the fourth G‐stretch. The presented hybrid‐type G‐quadruplex structure as determined by NMR spectroscopy may provide for an additional scaffold in quadruplex‐based technologies., Starting with a parallel‐stranded DNA G‐quadruplex, refolding into a novel (3+1) hybrid topology with a propeller‐propeller‐lateral loop architecture and an all‐syn 3’‐terminal G‐tract is reported. Although supported by additional stacking of a lateral duplex hairpin onto an outer G‐tetrad, the structural rearrangement must be enforced through the specific incorporation of syn‐favoring 8‐bromoguanosine analogues into the terminal G‐run.

A series of fluorescent ligands, which were systematically constructed from thiazole orange scaffold, was investigated for their interactions with G-quadruplex structures and antitumor activity. Among the ligands, compound 3 was identified to exhibit excellent specificity toward telomere G4-DNA over other nucleic acids. The affinity of 3-Htg24 was almost 5 times higher than that of double-stranded DNA and promoter G4-DNA. Interaction studies showed that 3 may bind to both G-tetrad and the lateral loop near the 5'-end. The intracellular colocalization with BG4 and competition studies with BRACO19 reveal that 3 may interact with G4-structures. Moreover, 3 reduces the telomere length and downregulates hTERC and hTERT mRNA expression in HeLa cells. The cytotoxicity of 3 against cancer cells (IC50 = 12.7-16.2 μM) was found to be generally higher than noncancer cells (IC50 = 52.3 μM). The findings may support that the ligand is telomere G4-DNA specific and may provide meaningful insights for anticancer drug design.

The triple-negative breast cancer (TNBC), a subtype of breast cancer which lacks of targeted therapies, exhibits a poor prognosis. It was shown recently that the PIM1 oncogene is highly related to the proliferation of TNBC cells. A quadruplex–duplex hybrid (QDH) forming sequence was recently found to exist near the transcription start site of PIM1. This structure could be an attractive target for regulation of the PIM1 gene expression and thus the treatment of TNBC. Here, we present the solution structures of two QDHs that could coexist in the human PIM1 gene. Form 1 is a three-G-tetrad-layered (3+1) G-quadruplex containing a propeller loop, a lateral loop and a stem-loop made up of three G•C Watson–Crick base pairs. On the other hand, Form 2 is an anti-parallel G-quadruplex comprising two G-tetrads and a G•C•G•C tetrad; the structure has three lateral loops with the middle stem-loop made up of two Watson-Crick G•C base pairs. These structures provide valuable information for the design of G-quadruplex-specific ligands for PIM1 transcription regulation.

Recently, the presence of i-motif structures at C-rich sequences in human cells and their regulatory functions have been demonstrated. Despite numerous steady-state studies on i-motif at neutral and slightly acidic pH, the number and nature of conformation of this biological structure are still controversial. In this work, the fluorescence lifetime of labelled molecular beacon i-motif-forming DNA sequences at different pH values is studied. The influence of the nature of bases at the lateral loops and the presence of a Watson–Crick-stabilized hairpin are studied by means of time-correlated single-photon counting technique. This allows characterizing the existence of several conformers for which the fluorophore has lifetimes ranging from picosecond to nanosecond. The information on the existence of different i-motif structures at different pH values has been obtained by the combination of classical global decay fitting of fluorescence traces, which provides lifetimes associated with the events defined by the decay of each sequence and multivariate analysis, such as principal component analysis or multivariate curve resolution based on alternating least squares. Multivariate analysis, which is seldom used for this kind of data, was crucial to explore similarities and differences of behaviour amongst the different DNA sequences and to model the presence and identity of the conformations involved in the pH range of interest. The results point that, for i-motif, the intrachain contact formation and its dissociation show lifetimes ten times faster than for the open form of DNA sequences. They also highlight that the presence of more than one i-motif species for certain DNA sequences according to the length of the sequence and the composition of the bases in the lateral loop., Funding from Spanish government [CTQ2014-61758-EXP, CTQ2014-52588-R, CTQ2015-66254-C2-2-P]; Autonomous Catalan government [2017SGR114]. Funding for open access charge: University of Bracelona [CTQ2015-66254-C2-2-P] and Université de Lille, LASIR CNRS.

Context. Prominence eruptions provide key observations to understand the launch of coronal mass ejections as their cold plasma traces a part of the unstable magnetic configuration. Aims. We select a well observed case to derive observational constraints for eruption models. Methods. We analyze the prominence eruption and loop expansion and contraction observed on 02 March 2015 associated with a GOES M3.7 class flare (SOL2015-03-02T15:27) using the data from Atmospheric Imaging Assembly (AIA) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We study the prominence eruption and the evolution of loops using the time-distance techniques. Results. The source region is a decaying bipolar active region where magnetic flux cancellation is present for several days before the eruption. AIA observations locate the erupting prominence within a flux rope viewed along its local axis direction. We identify and quantify the motion of loops in contraction and expansion located on the side of the erupting flux rope. Finally, RHESSI hard X-ray observations identify the loop top and two foot-point sources. Conclusions. Both AIA and RHESSI observations support the standard model of eruptive flares. The contraction occurs 19 minutes after the start of the prominence eruption indicating that this contraction is not associated with the eruption driver. Rather, this prominence eruption is compatible with an unstable flux rope where the contraction and expansion of the lateral loop is the consequence of a side vortex developing after the flux rope is launched., Comment: 16 pages, 9 figures, 1 table, and appendix

A (3+1)-hybrid-type G-quadruplex was substituted within its central tetrad by a single 2'-fluoro-modified guanosine. Driven by the anti-favoring nucleoside analogue, a novel quadruplex fold with inversion of a single G-tract and conversion of a propeller loop into a lateral loop emerges. In addition, scalar couplings across hydrogen bonds demonstrate the formation of intra- and inter-residual F⋅⋅⋅H8-C8 pseudo-hydrogen bonds within the modified quadruplexes. Alternative folding can be rationalized by the impact of fluorine on intermediate species on the basis of a kinetic partitioning mechanism. Apparently, chemical or other environmental perturbations are able to redirect folding of a quadruplex, possibly modulating its regulatory role in physiological processes.

We describe a patient who underwent arthroscopic pullout fixation for a posterior cruciate ligament (PCL) avulsion fracture. A 46-year-old female, injured in a fall while riding a motorcycle, was diagnosed with a right knee PCL tibial attachment avulsion fracture and underwent arthroscopic osteosynthesis. A Kirschner wire was drilled to a point just medial to the medial border of the anterior tibial bony bed. A suture wire was folded into a loop and introduced into the posteromedial compartment via the bone tunnel. A fixation thread was inserted from the posteromedial portal, through the medial and lateral loop wires, and into the posteromedial compartment. The lateral and medial loop wires attached to the thread were pulled to the outside, and the thread was fixed onto the tibia. Three months post-surgery, she returned to her job. This procedure represents a minimally invasive method of treating avulsion fractures of the tibial attachment of the PCL.

Lampbrush chromosomes are giant, transcriptionally active, meiotic chromosomes found in oocytes of all vertebrates with the exception of mammals. Lampbrush chromosomes offer a convenient tool for cytogenetic mapping and, in particular, have been instrumental in mapping genes and linkage groups on chicken (GGA) chromosomes. Whereas cytogenetic maps of macrochromosome GGA1-10 and microchromosome GGA11-16 lampbrush bivalents have been established, identification and description of smaller microchromosome bivalents are still missing. In this work, we used specific FISH probes for the identification of 12 chicken lampbrush chromosomes formed by GGA17-28. Our observations on chromomere and lateral loop arrangement and chiasma position allowed us to construct the respective cytogenetic maps for these microchromosomes. For the 10 smallest chicken microchromosomes, GGA29-38, no individual molecular tags are available, yet they can be collectively marked using the PO41 repeat. The reported results contribute to building of working cytogenetic maps of the chicken karyotype. (C) 2017 S.Karger AG, BaselKeywords

A novel homogenous fluorescent sensor for signal-on detection of Cu2+ has been developed based on intra-molecular G-quadruplex formed by DNA-templated click reaction and crystal violet (CV) as label-free signal reporter. The clickable DNA probe consists of two G-rich strands (A and B) bearing azide and alkyne group, respectively, and a template strand (C) locating two proximate reactants by pairing with A and B. The sequences of A and B are derived from asymmetric split of the G-quadruplex sequence (TTAGGG)4. In the presence of Cu2+, the whole G-quadruplex sequence A–B is generated by chemical ligation of A and B via copper ion-catalyzed alkyne-azide cycloaddition, then released from template by toehold strand displacement, and consequently forming a stable intra-molecular G-quadruplex, which binds with CV to generate a strong fluorescent signal. Oppositely, weak fluorescence was obtained without Cu2+ because of unstable intermolecular G-quadruplex formed by A and B and lack of lateral loop connection. Therefore, the Cu2+ can be sensitively and specifically detected by the fluorescence of the CV-stained G-quadruplex with a low detection limit of 65 nM and a linear range of 0.1–3 µM. This method rationally integrated the DNA-templated synthesis and G-quadruplex structure-switch, presenting a simple and promising approach for biosensor development.

Since the angled deck is only tens miles width, the task of landing an aircraft on an aircraft carrier requires precise control, especially lateral loop. For this problem, this paper focuses on researching the aircraft automatic landing lateral control. In lateral control, the most crucial parts are controlling the off center distance and keeping the desired landing attitude. So firstly a nonlinear kinetic model of aircraft landing in lateral directional axis is established, and then transformed into error states. The controller is designed for an angle of attack of 11.7 deg and an airspeed of 40m/s, the equilibrium point. Receding horizon control methodology is employed to solve the aircraft lateral control problem. This controller is solved in MATLAB, and sent to the 3D simulation environment by network communication, to control the aircraft landing lateral loop. The simulation environment is programmed based on VC++ software. The simulation results show that receding horizon control method can achieve trajectory tracking and attitude tracking of nonlinear aircraft landing system.

Hypersonic glide vehicles have strong lateral mobility which will lead to great bank-angle in flight. Hence, great longitudinal and lateral loop coupling will greatly increase the difficulty of guidance. Since traditional decoupling guidance strategy is difficult to adapt to this situation; to solve this problem, this paper introduces a concept of virtual displacement from analytical mechanics and designs virtual displacement guidance method for hypersonic glide vehicle, based on the small control changes' impact on the whole trajectory. In every guidance period, virtual displacement guidance method predicts the vehicle's landing point, searching the optimal bank-angle and angle of attack successively to correct the error. Simulation results show that virtual displacement is able to achieve higher guidance accuracy in both standard and uncertain conditions than traditional methods. In addition, lateral error corridor introduced can restrain the control's chatter phenomenon.

Overexpression of platelet-derived growth factor receptor β (PDGFR-β) has been associated with cancers and vascular and fibrotic disorders. PDGFR-β has become an attractive target for the treatment of cancers and fibrotic disorders. DNA G-quadruplexes formed in the GC-rich nuclease hypersensitivity element of the human PDGFR-β gene promoter have been found to inhibit PDGFR-β transcriptional activity. Here we determined the major G-quadruplex formed in the PDGFR-β promoter. Instead of using four continuous runs with three or more guanines, this G-quadruplex adopts a novel folding with a broken G-strand to form a primarily parallel-stranded intramolecular structure with three 1 nucleotide (nt) double-chain-reversal loops and one additional lateral loop. The novel folding of the PDGFR-β promoter G-quadruplex emphasizes the robustness of parallel-stranded structural motifs with a 1 nt loop. Considering recent progress on G-quadruplexes formed in gene-promoter sequences, we suggest the 1 nt looped G(i)NG(j) motif may have been evolutionarily selected to serve as a stable foundation upon which the promoter G-quadruplexes can build. The novel folding of the PDGFR-β promoter G-quadruplex may be attractive for small-molecule drugs that specifically target this secondary structure and modulate PDGFR-β gene expression.

Correlation analysis identified intrasensory and sensory-effector interactions of the interspike intervals of components of brainstem acoustic evoked potentials with measures of hand movement coordination. A role for the propagation of excitation via the ascending fibers of the rostral part of the pons and the lateral loop in the mechanisms of auditory-motor coordination was established. Gender differences were found in the integration of elements of the sensorimotor system depending on the lateralization of incoming auditory information and the complexity of the motor task performed. In men, the mechanism of auditory-motor coordination was less determined in nature than in women. This probably also determines their higher levelof bimanual coordination. The optimal error-free performance of the motor program in men was based on prognostication, while in women it was by correction of mistakes.

Background The lateral loop formed by the maxillary nerve (V2) and the mandibular nerve (V3) consists of a part of the far lateral triangle of the cavernous sinus. Because this triangle becomes a surgical corridor of the preauricular infratemporal fossa approach and a landmark of the extradural approach for the ganglion-type trigeminal schwannomas, identification of the lateral loop has important implications at the early stage of middle cranial base surgery. We realized that a bony ridge usually existed just lateral to the lateral loop. Objective To nominate midsubtemporal ridge (MSR) as the name for this anatomically unnamed bony ridge and to clarify its features. Methods Using 35 cadaver heads, we measured the shape of the MSR on both sides and the distance between the MSR and the adjacent structures. Results The MSR was recognized in 60 of 70 specimens (85.7%). The bony protrusion was 2.9 ± 1.1 mm in height, 6.0 ± 2.1 mm in width, and 9.1 ± 3.2 mm in length. A single peak with anteroposterior length was common in 47 of 60 specimens (78.3%). The MSR was located at the midpoint of the V2 and V3 in 28 specimens (46.7%) and existed 10.7 ± 3.6 mm lateral from the line that bound the foramen rotundum and the foramen ovale. Conclusion We demonstrate morphological characteristics of the MSR. These data on the MSR will assist the surgeon in identifying the lateral loop as a surgical landmark during middle cranial base surgery.

Platelet-derived growth factor receptor beta (PDGFR-β) is a cell-surface-receptor tyrosine kinase implicated in platelet-derived growth factor (PDGF) signaling pathways, and overexpression of PDGFR-β is associated with tumor growth, angiogenesis, and migration, making PDGFR-β an attractive target for cancer therapy. The formation of DNA G-quadruplexes in the GC-rich nuclease hypersensitivity element of the human PDGFR-β gene promoter has been found to inhibit PDGFR-β transcriptional activity. We previously determined the major G-quadruplex structure formed in the PDGFR-β promoter using a 22-mer sequence of pu22m1, which adopts a folding pattern containing a unique broken G-strand with the 3' tetrad-guanine coming from a distant site connected by a five nucleotide lateral loop. However, extension of the 3' end flanking segment of pu22m1 results in destabilization of the G-quadruplex, suggesting that this structure may be unstable in vivo. Recently, it has been reported that a unique type of intramolecular G-vacancy-bearing G-quadruplex (GVBQ) can be formed with three G3 tracts and one G2 tract and has an incomplete G-tetrad with a G-vacancy. A guanine derivative, such as GMP or GTP, can fill the G-vacancy with Hoogsteen hydrogen bonding and complete the G-tetrad, resulting in G-quadruplex stabilization. The unique broken-strand structure of PDGFR-β pu22m1 suggests a possibility of the formation of a GVBQ structure in this sequence, which can be completed and stabilized by guanine and guanine derivatives. To test this hypothesis, we examined the formation and stability of G-quadruplex formed in pu22m1 variants and the potential of guanine derivatives to fill in the incomplete G-tetrad and stabilize the overall G-quadruplex, using nuclear magnetic resonance spectroscopy, circular dichroism spectroscopy and DMS footprinting experiments. Our results showed that a GVBQ could form in in the PDGFR-β promoter sequence and that dGMP could insert and complete the incomplete G-tetrad to induce the formation of a stable and well-defined dGMP-fill-in-GVBQ in potassium solution. In addition, we discovered two natural plant alkaloids, berberine and chelerythrine, which could stabilize this dGMP-fill-in-GVBQ, with an increase in melting temperature by more than 10 °C. Therefore, it appears that dGMP could interact and stabilize the broken-stranded PDGFR-β promoter G-quadruplex, which may play a role in PDGFR-β transcriptional regulation. Elevated levels of guanine and guanine derivatives/metabolites are found in tumor cells, suggesting that the GVBQs may play important regulatory roles in tumor cell pathological processes, such as PDGFR-β transcriptional regulation. Furthermore, our results suggest that this unique dGMP-fill-in G-quadruplex in the PDGFR-β promoter may serve as a novel anticancer drug target for modulating PDGFR-β gene regulation. Citation Format: Kaibo Wang, Clement Lin, Guanhui Wu, Danzhou Yang. A dGMP fill-in G-quadruplex forms in the PDGFR-β promoter that serves as a unique target for drug design [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 687.

We report the NMR solution structure of the intramolecular G-quadruplex formed in human telomeric DNA in K(+). The hybrid-type telomeric G-quadruplex consists of three G-tetrads linked with mixed parallel-antiparallel G-strands, with the bottom two G-tetrads having the same G-arrangement (anti:anti:syn:anti) and the top G-tetrad having the reversed G-arrangement (syn:syn:anti:syn). The three TTA loop segments adopt different conformations, with the first TTA assuming a double-chain-reversal loop conformation, and the second and third TTA assuming lateral loop conformations. The NMR structure is very well defined, including the three TTA loops and the two flanking sequences at 5'- and 3'-ends. Our study indicates that the three loop regions interact with the core G-tetrads in a specific way that defines and stabilizes the unique human telomeric G-quadruplex structure in K(+). Significantly, a novel adenine triple platform is formed with three naturally occurring adenine residues, A21, A3 and A9, capping the top tetrad of the hybrid-type telomeric G-quadruplex. This adenine triple is likely to play an important role in the formation of a stable human telomeric G-quadruplex structure in K(+). The unique human telomeric G-quadruplex structure formed in K(+) suggests that it can be specifically targeted for anticancer drug design.

The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It usually arises at the anterolateral margin of the medulla oblongata close to the lower cranial nerves. The PICA had the most complex relationship to the cranial nerves of any artery and it is frequently exposed in approaches directed to the fourth ventricle. The aim of this article is to describe the anatomical relationship of the PICA to the lower cranial nerves. In this study, 12.5% of PICAs passed between the glossopharyngeal and vagus nerves, 20% between the vagus and accessory nerves, and 65% through the rootlets of the accessory nerve. The lateral medullary segment of the PICA showed a lateral loop which in 20% specimens pressed against the inferior surfaces of the facial and vestibulocochlear nerves. The lateral medullary segment of the PICA in 20% specimens passed superior to the hypoglossal nerve, in 47.5% through the rootlets of the hypoglossal nerve, and in 30% inferior to the hypoglossal nerve. The findings on the relationship of the PICA to the lower cranial nerves could be helpful in microsurgery of this region.

BCL2 protein functions as an inhibitor of cell apoptosis and has been found to be aberrantly expressed in a wide range of human diseases. A highly GC-rich region upstream of the P1 promoter plays an important role in the transcriptional regulation of BCL2. Here we report the NMR solution structure of the major intramolecular G-quadruplex formed on the G-rich strand of this region in K+ solution. This well-defined mixed parallel/antiparallel-stranded G-quadruplex structure contains three G-tetrads of mixed G-arrangements, which are connected with two lateral loops and one side loop, and four grooves of different widths. The three loops interact with the core G-tetrads in a specific way that defines and stabilizes the overall G-quadruplex structure. The loop conformations are in accord with the experimental mutation and footprinting data. The first 3-nt loop adopts a lateral loop conformation and appears to determine the overall folding of the BCL2 G-quadruplex. The third 1-nt double-chain-reversal loop defines another example of a stable parallel-stranded structural motif using the G3NG3 sequence. Significantly, the distinct major BCL2 promoter G-quadruplex structure suggests that it can be specifically involved in gene modulation and can be an attractive target for pathway-specific drug design.

OBJECTIVE: The purpose of this study is to call attention to an anomaly in which a segment of the anteroinferior cerebellar artery (AICA) is embedded in the dura or bone surrounding the subarcuate fossa, a small depression in the bone posterior to the internal acoustic meatus (IAM), through which the subarcuate artery enters the bone. This anomaly places the artery at risk in removing the posterior wall of the IAM. METHODS: An anomalous AICA having a segment that was embedded in the dura covering on the bone surrounding the subarcuate fossa was found during a microsurgical dissection course. The senior author (ALR) has observed this anomaly in four patients during surgery for acoustic neuromas and in three specimens in microsurgery dissection courses. To define the microsurgical anatomy of the anomalous artery further, the latex-injected specimen was dissected in a stepwise manner using ×3 to ×40 magnification. RESULTS: The anomalous AICA described in this report bifurcated into a rostral trunk and a caudal trunk near the facial-vestibulocochlear nerve complex. The caudal trunk formed a sharp lateral loop that was embedded in the dura covering the subarcuate fossa. The involved trunk continued to supply the suboccipital area normally supplied by the posteroinferior cerebellar artery, which was hypoplastic. The dura surrounding the anomalous loop was opened, and the adjacent bone was removed to free the anomalous loop from the subarcuate fossa so that the artery could be displaced medially to remove the posterior wall of the IAM. Although it has been reported that the AICA may occasionally be adherent to the dura over the subarcuate fossa, this study is the first to demonstrate an AICA that is embedded in the dura and bone of the subarcuate fossa. CONCLUSION: Mobilizing the AICA loop that is embedded in the subarcuate fossa posterior to the IAM places the involved AICA at significant risk in exposing the contents of the IAM.

Dengue virus (DV) is a flavivirus and infects mammalian cells through mosquito vectors. This study investigates the roles of domain III of DV type 2 envelope protein (EIII) in DV binding to the host cell. Recombinant EIII interferes with DV infection to BHK21 and C6/36 cells by blocking dengue virion adsorption to these cells. Inhibition of EIII on BHK21 cells was broad with no serotype specificity; however, inhibition of EIII on C6/36 cells was relatively serotype specific. Soluble heparin completely blocks binding of EIII to BHK21 cells, suggesting that domain III binds mainly to cell surface heparan sulfates. This suggestion is supported by the observation that EIII binds very weakly to gro2C and sog9 mutant mammalian cell lines that lack heparan sulfate. In contrast, heparin does not block binding of EIII to mosquito cells. Furthermore, a synthetic peptide that includes amino acids (aa) 380 to 389 of EIII, IGVEPGQLKL, inhibits binding of EIII to C6/36 but not BHK21 cells. This peptide corresponds to a lateral loop region on domain III of E protein, indicating a possible role of this loop in binding to mosquito cells. In summary, these results suggest that EIII plays an important role in binding of DV type 2 to host cells. In addition, EIII interacts with heparan sulfates when binding to BHK21 cells, and a loop region containing aa 380 to 389 of EIII may participate in DV type 2 binding to C6/36 cells.

The purpose of this report is to determine the applicability of the Quantitative Feedback Theory (QFT) approach to designing the control laws for a modern military flight control system. This report documents a portion of the QFT research program, specifically, the implementation of a QFT design on a manned simulation of the NF-16D Variable Stability Inflight Simulator Test Aircraft (VISTA F-16). The control law design addresses the subsonic flight envelope of the VISTA F-16 including changes in aircraft configuration. The design was accomplished as a SISO longitudinal loop and a MIMO lateral loop, and incorporates pilot handling qualities within the specifications. Imbedding handling qualities in the system through prudent choice of control variable ensured that the performance specifications were met. Flexibility in the prefilter design allowed the closed loop response to be shaped for proper feel. The handling qualities were evaluated in a high fidelity, manned simulation of the system. The QFT design provided level 1 handling qualities per the specifications in the pitch channel. It did not provide level 1 handling qualities in the lateral channel, but the design requires minor modification to meet level 1.

“Ever since the gene hypothesis was generally accepted, geneticists and cytologists have dreamed of the day when it would be possible to see the actual genes, instead of having to be satisfied with studying their “shadows”, which were “reflected” in the morphological development of generations of organisms” (T S Painter, 1934).

In the present study we assessed pleiotropic characteristics of the antibody-selected mutations. We examined pH optimum of fusion, temperatures of HA heat inactivation, and in vitro and in vivo replication kinetics of the previously obtained influenza H5 escape mutants. Our results showed that HA1 N142K mutation significantly lowered the pH of fusion optimum. Mutations of the escape mutants located in the HA lateral loop significantly affected H5 HA thermostability (P

Overexpression of platelet-derived growth factor receptor β (PDGFR-β) is associated with multiple cancers, making PDGFR-β an attractive target for anticancer drugs. Few strategies other than molecular targeting of the PDGFR-β protein or its cognate ligand have been reported for developing inhibitors for the PDGFR-β signaling pathway. DNA G-quadruplexes (G4s) formed in the GC-rich nuclease hypersensitivity element of the human PDGFR-β gene promoter have been found to inhibit PDGFR-β transcriptional activity, and stabilization of these G4s by small-molecule compounds could serve as a mechanism for cancer therapeutics. We have shown that the major G4 formed in the PDGFR-β promoter is from the central four G-runs, adopting an intramolecular parallel-stranded structure with a broken G-strand and contains three 1-nucleotide (nt) chain-reversal loops and one lateral loop. The novel folding of the PDGFR-β G4 highlights the inherent stability of the 1-nt loops in parallel-stranded G4 structures. Elucidating the structure of the major PDGFR-β promoter G4 is important for designing small-molecule drugs to specifically target this structure to inhibit gene transcription. Using nuclear magnetic resonance (NMR) spectroscopy, we have determined the potassium solution structure of this major G4 formed in the PDGFR-β promoter. Our structure showed a unique 3’ capping structure involving three guanine nucleotides in the lateral loop. This novel capping structure is determined by the specific loop sequence as well as the broken-stranded PDGFR-β G4 folding pattern. The unique 3’ capping structure could be specifically recognized by proteins and small molecule ligands. Unrestrained molecular dynamic calculations showed that this major PDGFR-β G4 and its 3’ capping structure are stable in aqueous environment on the ns time-scale. We also investigated the binding of small-molecules to the PDGFR-β G4 using a combination of NMR, circular dichroism (CD), and fluorescence based methods to identify compounds that can selectively bind the PDGFR-β G4 over other classic parallel-stranded G-quadruplexes, such as the c-MYC promoter G4. Our study demonstrates the structural diversity in promoter G4s which may enable specific recognition and the modulation of gene expression by small-molecule drugs. Citation Format: Clement Lin, Prashansa Agrawal, Yuwei Chen, Salil Kalarn, Nanjie Deng, Laurence Hurley, Danzhou Yang. Molecular structure of the major G-quadruplex formed in the PDGFR-β promoter nuclease hypersensitivity element and its binding with small molecules. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3090.

Various surgical approaches to the infratemporal fossa (ITF) have been reported. Among them, the preauricular transzygomatic anterior ITF approach (anterior ITF approach) has been used for exposure of the antero-superior part of the ITF. The purpose of this article is to show anatomical dissections using the anterior ITF approach and to evaluate our surgical experience using this approach. An anatomical study of the anterior ITF approach was performed using six sides of three cadaveric heads. Clinical course was retrospectively reviewed for 34 patients who underwent microsurgical resection of tumor in or around the ITF using this approach. Medical, surgical, and neuroimaging records of these patients were evaluated. The key point of this approach was mobilization of the second and third divisions of the trigeminal nerve after drilling of the lateral loop between the foramina rotundum and ovale. After mobilization of the trigeminal nerve, the auditory tube, tensor veli palatini muscle, and pharyngobasilar membrane could be seen. Removal of the pterygoid muscles and plates allowed surgical access to the ITF, orbit, maxillary sinus, pterygopalatine fossa, and parapharyngeal space. We used this approach in 31 patients with skull base tumors between 1994 and 2007. Gross total removal was achieved in 27 of the 31 patients. No mortality or severe morbidity was encountered. Therefore, the anterior ITF approach provides easy access to the ITF and adjacent regions without destruction of important organs.

TMPyP4 (Mesotetra(N-methyl-4-pyridyl)porphine) is known to have a high affinity for G-quadruplex DNA. However, there is still some controversy over the exact site(s) and mode(s) of TMPyP4 binding to G-quadruplex DNA. We examined TMPyP4 interactions with seven G-quadruplex forming oligonucleotides. The parent oligonucleotide is a 27-mer with a wild-type (WT) G-rich sequence of the Bcl-2 P1 promoter mid-region (5'-d(CGG GCG CGG GAG GAA GGG GGC GGG AGC-3')). This sequence folds into at least three unique loop isomer quadruplexes. The two mutant oligonucleotides used in this study are shorter (23-mer) sequences in which nonquadruplex core bases were eliminated and two different (-G-G-) --(-T-T-) substitutions were made to restrict the folding complexity. The four additional mutant oligonucleotides were labeled by substituting a 2-aminopurine (2-AP) base for an A or G in either the first three-base lateral loop or the second five- or seven-base lateral loop (depending on the G--T mutation positions). Spectroscopic and microcalorimetric studies indicate that four molecules of TMPyP4 can be bound to a single G-quadruplex. Binding of the first two moles of TMPyP4 appears to occur by an end or exterior mode (K approximately 1 x 10(7) M(-1)), whereas binding of the third and fourth moles of TMPyP4 appears to occur by a weaker, intercalative binding mode (K approximately 1 x 10(5) M(-1)). As the mid-loop size decreases from seven to five bases, end binding occurs with significantly increased affinity. 2-AP-labeled Bcl-2 promoter region quadruplexes show increased fluorescence of the 2-AP base on addition of TMPyP4. The change in fluorescence for 2-AP bases in the second half of the TMPyP4 titration lends support to our previous speculation regarding the intercalative nature of the weaker binding mode.

Twelve patients with catatonic schizophrenia and 12 matched healthy controls were examined with functional MRI while performing a motor task. The aim of our study was to identify the intracerebral pathophysiological correlates of motor symptoms in catatonic patients. The motor task included three conditions: a self-initiated (SI), an externally triggered (ET) and a rest condition. Statistical analysis was performed with SPM5. During the self-initiated movements patients showed significantly less activation than healthy controls in the supplementary motor area (SMA), the prefrontal and parietal cortex. Our results suggest a dysfunction of the "medial motor system" in catatonic patients. Self-initiated and externally triggered movements are mediated by different motor loops. The "medial loop" includes the SMA, thalamus and basal ganglia, and is necessary for self-initiated movements. The "lateral loop" includes parts of the cerebellum, lateral premotor cortex, thalamus and parietal association areas. It is involved in the execution of externally triggered movements. Our findings are in agreement with earlier behavioral data, which show deficits in self-initiated movements in catatonic patients but no impairment of externally triggered movements.

Connections between the hypothalamus and brainstem formations were investigated inOphisaurus apodus by locally injecting horseradish peroxidase (HP) or lectin-HP into the mamillary complex and the hypothalamo-tegmental area of the brain. Direct reciprocal connections were found linking mamillary complex nuclei and posterior and lateral hypothalamic structures with the following brainstem formations: central gray matter, parabrachial nucleus, raphe nuclei and the lateral loop, reticular formation of the caudal mesencephalon, pons, and medulla. It was concluded that direct bilateral hypothalamo-brainstem connections were already in place in reptiles, serving as the basis for sympatho-emotional nociceptive, and antinociceptive response.

The chromosomal distribution of 41-bp repeats, known as CNM and PO41 repeats in the chicken genome and BglII repeats in the Japanese quail, was analyzed precisely using giant lampbrush chromosomes (LBC) from chicken, Japanese quail, and turkey growing oocytes. The PO41 repeat is conserved in all galliform species, whereas the other repeats are species specific. In chicken and quail, the centromere and subtelomere regions share homologous satellite sequences. RNA polymerase II transcribes the 41-bp repeats in both centromere and subtelomere regions. Ongoing transcription of these repeats was demonstrated by incorporation of BrUTP injected into oocytes at the lampbrush stage. RNA complementary to both strands of CNM and PO41 repeats is present on chicken LBC loops, whereas strand-specific G-rich transcripts are characteristic of BglII repeats in the Japanese quail. The RNA from 41-bp repeats does not undergo cotranscriptional U snRNP-dependent splicing. At the same time, the ribonucleoprotein matrix of transcription units with C-rich RNA of CNM and PO41 repeats was enriched with hnRNP protein K. Potential promoters for satellite transcription are discussed.

The shell morphology and anatomy of two enigmatic Pisidium species, Pisidium dorbignyi Clessin, 1879, never re-examined after the original description, and Pisidium lebruni Mabille, 1884, a species not reported again until 1995, are described. The type of P. dorbignyi (new name for Cyclas pulchella d´Orbigny, 1835) is lost, for which, and in order to define the taxonomic status of the species, a neotype is herein selected. Both species share as common features: the presence of only the anal siphonal aperture, only one pair of demibranchs, the inner and the type of nephridium, closed with lateral loop visible from dorsal view, consistently differing in shell morphology. Previously unknown details on the anatomy of Pisidium sterkianum Pilsbry, 1897 and Pisidium vile Pilsbry, 1897, particularly those concerning the type of nephridium and inner radial mantle musculature, are described and illustrated for the first time.

B lymphocytes express the nonclassical class II molecule HLA-DO, which modulates the peptide loading activity of HLA-DM in the endocytic pathway. Binding to HLA-DM is required for HLA-DO to egress from the endoplasmic reticulum (ER). To gain insights into the mode of action of DO and on the role of DM in ER release, we sought to identify DM-binding residues on DO. Our results show that DOalpha encompasses the binding site for HLA-DM. More specifically, mutation of residue DOalpha41 on an exposed lateral loop of the alpha1 domain affects the binding to DM, ER egress, and activity of DO. Using a series of chimeric DR/DO molecules, we confirmed the role of the alpha chain and established that a second DM-binding region is located C-terminal to the DOalpha80 residue, most probably in the alpha2 domain. Interestingly, after mutation of a buried proline (alpha11) on the floor of the putative peptide-binding groove, HLA-DO remained functional but became independent of HLA-DM for ER egress and intracellular trafficking. Collectively, these results suggest that the binding of HLA-DM to DOalpha allows the complex to egress from the ER by stabilizing intramolecular contacts between the N-terminal antiparallel beta-strands of the DOalphabeta heterodimer.

Arthroscopic-assisted simultaneous reconstruction of the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL) using hamstring tendon grafts is described. The femoral tunnel is drilled through an incision over the medial femoral condyle and the tibial tunnel through the same skin incision used for harvesting the tendon graft. PCL reconstruction is performed using a 4-strand hamstring tendon graft and absorbable screw fixation. The tendon of the semitendinosus muscle of the uninvolved knee is used as a lateral loop for LCL reconstruction. After pulling the transplant through the fibular head, femoral fixation of the loop is made with an absorbable screw.

Background: Telomeres in eukaryotic organisms are protein–DNA complexes which are essential for the protection and replication of chromosomal termini. The telomeric DNA of Tetrahymena consists of T 2 G 4 repeats, and models have been previously proposed for the intramolecular folded structure of the d(T 2 G 4 ) 4 sequence based on chemical footprinting and cross-linking data. Ahigh-resolution solution structure of this sequence would allow comparison with the structures of related G–tetraplexes. Results The solution structure of the Na + –stabilized d(T 2 G 4 ) 4 sequence has been determined using a combined NMR–molecular dynamics approach. The sequence folds intramolecularly into a right-handed G–tetraplex containing three stacked G-tetrads connected by linker segments consisting of a G-T-T-G lateral loop, a central T-T-G lateral loop and a T-T segment that spans the groove through a double chain reversal. Te latter T–T connectivity aligns adjacent G-G-G segments in parallel and introduces a new G-tetraplex folding topology with unprecedented combinations of strand directionalities and groove widths, as well as guanine syn/anti distributions along individual strands and around individual G-tetrads. Conclusion The four repeat Tetrahymena and human G-tetraplexes, which differ by a single guanine for adenine substitution, exhibit strikingly different folding topologies. The observed structural polymorphism establishes that G-tetraplexes can adopt topologies which project distinctly different groove dimensions, G-tetrad base edges and linker segments for recognition by, and interactions with, other nucleic acids and proteins.

The ZW bivalent has been identified and characterized in detail in its lampbrush form in oocytes of chicken, quail, turkey, pigeon, chaffinch and sparrow. The sex bivalent in all six species looks like a single highly asymmetrical chromosome. Most of it has the typical lampbrush organization. The terminal one-fifth is relatively thick and condensed and bears only a few pairs of lateral loops: this condensed terminal region is the W chromosome; the part with normal lampbrush morphology is the Z. The two are connected by a single near terminal chiasma. The fine scale morphology and arrangement of loops and markers on Z and W chromosomes are described for each species and lampbrush maps have been constructed. The identification of the lampbrush sex bivalent is based on the following criteria. The asymmetrical chromosome has two centromere regions. In the interstitial region of the asymmetrical chromosome where the junction between Z and W chromosomes is supposed to be, there are telomere-specific loops and telomeric DNA sequences and there is good morphological evidence for the presence of a chiasma. There are W chromosome specific DNA sequences in the region of the asymmetrical lampbrush chromosome that is thought to represent the W. Breed-specific variations in the morphology of the chicken W chromosome with respect to the sizes, numbers and arrangements of axial chromomeres and distributions of specified repeated DNA sequence families have been identified, offering one of the first examples of definitive correlation between a repeat family and a single chromomere. The lampbrush chromosomes of all the birds examined, except quail, terminate in distinctive free hanging loops. These are a novel feature in the sense that at the end of each chromatid there is a large transcription unit terminating in a cluster of telomeric DNA sequences.

A British sickle socketed laterally (Group I, C. F'ox, 1939) has been discovered around «La Chapelle-des- Marais» (Loire-Atlantique). Typical objects of the carp's tongue group, this kind of sickles is a proof showing a link berween British islands and France during the Bronze Age., Une faucille à douille latérale de type britannique (groupe I de C. Fox, 1939) a été retrouvée sur la commune de la Chapelle-des-Marais (Loire -Atlantique). Généralement associées à des objets caractéristiques du complexe à l'épée «langue de carpe», ces faucilles sont datées du Bronze Final III. Originaires d'outre Manche, elles représentent un intéressant témoin des relations unissant les Iles Britanniques et la France tout au long du Bronze Final., Maggi Christine, Faye Chrystèle. Découverte d'une faucille à douille de type britannique sur la commune de la Chapelle-des-Marais (Loire-Atlantique). In: Revue archéologique de l'ouest, tome 8, 1991. pp. 99-102.

Ultrasound vibrators (titanium stepped horns at 20 kHz) themselves were used as cathodes for electroreduction of benzaldehydes in a methanolic sulfuric acid solution. Three types of vibrating cathode were prepared by partitioning the surface of the horns with insulating materials: tip-section loop, lateral node and lateral loop cathodes. The current efficiency for reduction and product selectivity for the corresponding hydrodimeric products were increased with increasing ultrasound oscillating power in different manners on the cathodes. The lateral cathodes could exhibit the effect at relatively low ultrasonic powers compared with the sectional one. In addition, higher efficiency and selectivity were obtained at the lateral loop cathode than at the node one.