bluuebunny/crossref_metadata_2025 huggingface dataset:
Revealing the competition between peeled ssDNA, melting bubbles, and S-DNA during DNA overstretching using fluorescence microscopy
Authors: King Graeme A. , Gross Peter , Bockelmann Ulrich , Modesti Mauro , Wuite Gijs J. L. , Peterman Erwin J. G.
Published: February 2013

Mechanical stress plays a key role in many genomic processes, such as DNA replication and transcription. The ability to predict the response of double-stranded (ds) DNA to tension is a cornerstone of understanding DNA mechanics. It is widely appreciated that torsionally relaxed dsDNA exhibits a structural transition at forces of ∼65 pN, known as overstretching, whereby the contour length of the molecule increases by ∼70%. Despite extensive investigation, the structural changes occurring in DNA during overstretching are still generating considerable debate. Three mechanisms have been proposed to account for the increase in DNA contour length during overstretching: strand unpeeling, localized base-pair breaking (yielding melting bubbles), and formation of S-DNA (strand unwinding, while base pairing is maintained). Here we show, using a combination of fluorescence microscopy and optical tweezers, that all three structures can exist, uniting the often contradictory dogmas of DNA overstretching. We visualize and distinguish strand unpeeling and melting-bubble formation using an appropriate combination of fluorescently labeled proteins, whereas remaining B-form DNA is accounted for by using specific fluorescent molecular markers. Regions of S-DNA are associated with domains where fluorescent probes do not bind. We demonstrate that the balance between the three structures of overstretched DNA is governed by both DNA topology and local DNA stability. These findings enhance our knowledge of DNA mechanics and stability, which are of fundamental importance to understanding how proteins modify the physical state of DNA.
Single-channel basis for the slow activation of the repolarizing cardiac potassium current,
I

Ks
Authors: Werry Daniel , Eldstrom Jodene , Wang Zhuren , Fedida David
Published: February 2013

Coassembly of potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1) with potassium voltage-gated channel, Isk-related family, member 1 (KCNE1) the delayed rectifier potassium channel
I

Ks

. Its slow activation is critically important for membrane repolarization and for abbreviating the cardiac action potential, especially during sympathetic activation and at high heart rates. Mutations in either gene can cause long QT syndrome, which can lead to fatal arrhythmias. To understand better the elementary behavior of this slowly activating channel complex, we quantitatively analyzed direct measurements of single-channel
I

Ks

. Single-channel recordings from transiently transfected mouse
ltk
−
cells confirm a channel that has long latency periods to opening (1.67 ± 0.073 s at +60 mV) but that flickers rapidly between multiple open and closed states in non-deactivating bursts at positive membrane potentials. Channel activity is cyclic with periods of high activity followed by quiescence, leading to an overall open probability of only ∼0.15 after 4 s under our recording conditions. The mean single-channel conductance was determined to be 3.2 pS, but unlike any other known wild-type human potassium channel, long-lived subconductance levels coupled to activation are a key feature of both the activation and deactivation time courses of the conducting channel complex. Up to five conducting levels ranging from 0.13 to 0.66 pA could be identified in single-channel recordings at 60 mV. Fast closings and overt subconductance behavior of the wild-type
I

Ks

channel required modification of existing Markov models to include these features of channel behavior.
Recent land use change in the Western Corn Belt threatens grasslands and wetlands
Authors: Wright Christopher K. , Wimberly Michael C.
Published: February 2013

In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0–5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.
On molecular origin of mass-independent fractionation of oxygen isotopes in the ozone forming recombination reaction
Authors: Ivanov Mikhail V. , Babikov Dmitri
Published: February 2013

Theoretical treatment of ozone forming reaction is developed within the framework of mixed quantum/classical dynamics. Formation and stabilization steps of the energy transfer mechanism are both studied, which allows simultaneous capture of the delta zero-point energy effect and η-effect and identification of the molecular level origin of mass-independent isotope fractionation. The central role belongs to scattering resonances; dependence of their lifetimes on rotational excitation, asymmetry; and connection of their vibrational wave functions to two different reaction channels. Calculations, performed within the dimensionally reduced model of ozone, are in semiquantitative agreement with experiment.
Contribution of α7 nicotinic receptor to airway epithelium dysfunction under nicotine exposure
Authors: Maouche Kamel , Medjber Kahina , Zahm Jean-Marie , Delavoie Franck , Terryn Christine , Coraux Christelle , Pons Stéphanie , Cloëz-Tayarani Isabelle , Maskos Uwe , Birembaut Philippe , Tournier Jean-Marie
Published: February 2013

Loss or dysfunction of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) leads to impairment of airway mucus transport and to chronic lung diseases resulting in progressive respiratory failure. Nicotinic acetylcholine receptors (nAChRs) bind nicotine and nicotine-derived nitrosamines and thus mediate many of the tobacco-related deleterious effects in the lung. Here we identify α7 nAChR as a key regulator of CFTR in the airways. The airway epithelium in α7 knockout mice is characterized by a higher transepithelial potential difference, an increase of amiloride-sensitive apical Na
+
absorption, a defective cAMP-dependent Cl
−
conductance, higher concentrations of Na
+
, Cl
−
, K
+
, and Ca
2+
in secretions, and a decreased mucus transport, all relevant to a deficient CFTR activity. Moreover, prolonged nicotine exposure mimics the absence of α7 nAChR in mice or its inactivation in vitro in human airway epithelial cell cultures. The functional coupling of α7 nAChR to CFTR occurs through Ca
2+
entry and activation of adenylyl cyclases, protein kinase A, and PKC. α7 nAChR, CFTR, and adenylyl cyclase-1 are physically and functionally associated in a macromolecular complex within lipid rafts at the apical membrane of surface and glandular airway epithelium. This study establishes the potential role of α7 nAChR in the regulation of CFTR function and in the pathogenesis of smoking-related chronic lung diseases.
Related F-box proteins control cell death in
Caenorhabditis elegans
and human lymphoma
Authors: Chiorazzi Michael , Rui Lixin , Yang Yandan , Ceribelli Michele , Tishbi Nima , Maurer Carine W. , Ranuncolo Stella M. , Zhao Hong , Xu Weihong , Chan Wing-Chung C. , Jaffe Elaine S. , Gascoyne Randy D. , Campo Elias , Rosenwald Andreas , Ott German , Delabie Jan , Rimsza Lisa M. , Shaham Shai , Staudt Louis M.
Published: February 2013

Cell death is a common metazoan cell fate, and its inactivation is central to human malignancy. In
Caenorhabditis elegans
, apoptotic cell death occurs via the activation of the caspase CED-3 following binding of the EGL-1/BH3-only protein to the antiapoptotic CED-9/BCL2 protein. Here we report a major alternative mechanism for caspase activation in vivo involving the F-box protein DRE-1. DRE-1 functions in parallel to EGL-1, requires CED-9 for activity, and binds to CED-9, suggesting that DRE-1 promotes apoptosis by inactivating CED-9. FBXO10, a human protein related to DRE-1, binds BCL2 and promotes its degradation, thereby initiating cell death. Moreover, some human diffuse large B-cell lymphomas have inactivating mutations in
FBXO10
or express
FBXO10
at low levels. Our results suggest that DRE-1/FBXO10 is a conserved regulator of apoptosis.
Global structural motions from the strain of a single hydrogen bond
Authors: Danielsson Jens , Awad Wael , Saraboji Kadhirvel , Kurnik Martin , Lang Lisa , Leinartaitė Lina , Marklund Stefan L. , Logan Derek T. , Oliveberg Mikael
Published: February 2013

The origin and biological role of dynamic motions of folded enzymes is not yet fully understood. In this study, we examine the molecular determinants for the dynamic motions within the β-barrel of superoxide dismutase 1 (SOD1), which previously were implicated in allosteric regulation of protein maturation and also pathological misfolding in the neurodegenerative disease amyotrophic lateral sclerosis. Relaxation-dispersion NMR, hydrogen/deuterium exchange, and crystallographic data show that the dynamic motions are induced by the buried H43 side chain, which connects the backbones of the Cu ligand H120 and T39 by a hydrogen-bond linkage through the hydrophobic core. The functional role of this highly conserved H120–H43–T39 linkage is to strain H120 into the correct geometry for Cu binding. Upon elimination of the strain by mutation H43F, the apo protein relaxes through hydrogen-bond swapping into a more stable structure and the dynamic motions freeze out completely. At the same time, the holo protein becomes energetically penalized because the twisting back of H120 into Cu-bound geometry leads to burial of an unmatched backbone carbonyl group. The question then is whether this coupling between metal binding and global structural motions in the SOD1 molecule is an adverse side effect of evolving viable Cu coordination or plays a key role in allosteric regulation of biological function, or both?
The δ2 glutamate receptor gates long-term depression by coordinating interactions between two AMPA receptor phosphorylation sites
Authors: Kohda Kazuhisa , Kakegawa Wataru , Matsuda Shinji , Yamamoto Tadashi , Hirano Hisashi , Yuzaki Michisuke
Published: February 2013

Significance

Long-term depression (LTD) commonly affects learning and memory in various brain regions. Although LTD in the cerebellum absolutely requires δ2 glutamate receptors, its underlying mechanisms remain elusive. LTD is caused by endocytosis of AMPA receptors, which is triggered by activity-induced serine phosphorylation of the GluA2 subunit. Our work showed that this serine phosphorylation required prior dephosphorylation of the nearby tyrosine residue. By interaction with a tyrosine phosphatase, δ2 glutamate receptors regulated tyrosine dephosphorylation status of GluA2 to gate inducibility of LTD. These findings will provide better understanding of general mechanisms regulating AMPA receptor endocytosis during synaptic plasticity.
Reactive astrocytes secrete lcn2 to promote neuron death
Authors: Bi Fangfang , Huang Cao , Tong Jianbin , Qiu Guang , Huang Bo , Wu Qinxue , Li Fang , Xu Zuoshang , Bowser Robert , Xia Xu-Gang , Zhou Hongxia
Published: February 2013

Glial reaction is a common feature of neurodegenerative diseases. Recent studies have suggested that reactive astrocytes gain neurotoxic properties, but exactly how reactive astrocytes contribute to neurotoxicity remains to be determined. Here, we identify lipocalin 2 (lcn2) as an inducible factor that is secreted by reactive astrocytes and that is selectively toxic to neurons. We show that lcn2 is induced in reactive astrocytes in transgenic rats with neuronal expression of mutant human TAR DNA-binding protein 43 (TDP-43) or RNA-binding protein fused in sarcoma (FUS). Therefore, lcn2 is induced in activated astrocytes in response to neurodegeneration, but its induction is independent of TDP-43 or FUS expression in astrocytes. We found that synthetic lcn2 is cytotoxic to primary neurons in a dose-dependent manner, but is innocuous to astrocytes, microglia, and oligodendrocytes. Lcn2 toxicity is increased in neurons that express a disease gene, such as mutant FUS or TDP-43. Conditioned medium from rat brain slice cultures with neuronal expression of mutant TDP-43 contains abundant lcn2 and is toxic to primary neurons as well as neurons in cultured brain slice from WT rats. Partial depletion of lcn2 by immunoprecipitation reduced conditioned medium-mediated neurotoxicity. Our data indicate that reactive astrocytes secrete lcn2, which is a potent neurotoxic mediator.
Mechanistic link between β barrel assembly and the initiation of autotransporter secretion
Authors: Pavlova Olga , Peterson Janine H. , Ieva Raffaele , Bernstein Harris D.
Published: February 2013

Significance

Most proteins that reside in the bacterial outer membrane are β sheets that fold into a unique cylindrical structure known as a “β barrel.” Here we describe significant insights into the function of the Bam complex, a protein machine that catalyzes the insertion of β barrel proteins into the membrane by an unknown mechanism. By analyzing the assembly of autotransporters, a specialized family of outer membrane proteins, we found that the function of the Bam complex can be divided into an initial substrate binding stage and a subsequent insertion stage that is surprisingly sensitive to structural distortions in client proteins.
Metabotropic NMDA receptor function is required for β-amyloid–induced synaptic depression
Authors: Kessels Helmut W. , Nabavi Sadegh , Malinow Roberto
Published: February 2013

The mechanisms by which β-amyloid (Aβ), a peptide fragment believed to contribute to Alzheimer’s disease, leads to synaptic deficits are not known. Here we find that elevated oligomeric Aβ requires ion flux-independent function of NMDA receptors (NMDARs) to produce synaptic depression. Aβ activates this metabotropic NMDAR function on GluN2B-containing NMDARs but not on those containing GluN2A. Furthermore, oligomeric Aβ leads to a selective loss of synaptic GluN2B responses, effecting a switch in subunit composition from GluN2B to GluN2A, a process normally observed during development. Our results suggest that conformational changes of the NMDAR, and not ion flow through its channel, are required for Aβ to produce synaptic depression and a switch in NMDAR composition. This Aβ-induced signaling mediated by alterations in GluN2B conformation may be a target for therapeutic intervention of Alzheimer’s disease.
Molecular basis for manganese sequestration by calprotectin and roles in the innate immune response to invading bacterial pathogens
Authors: Damo Steven M. , Kehl-Fie Thomas E. , Sugitani Norie , Holt Marilyn E. , Rathi Subodh , Murphy Wesley J. , Zhang Yaofang , Betz Christine , Hench Laura , Fritz Günter , Skaar Eric P. , Chazin Walter J.
Published: February 2013

The S100A8/S100A9 heterodimer calprotectin (CP) functions in the host response to pathogens through a mechanism termed “nutritional immunity.” CP binds Mn
2+
and Zn
2+
with high affinity and starves bacteria of these essential nutrients. Combining biophysical, structural, and microbiological analysis, we identified the molecular basis of Mn
2+
sequestration. The asymmetry of the CP heterodimer creates a single Mn
2+
-binding site from six histidine residues, which distinguishes CP from all other Mn
2+
-binding proteins. Analysis of CP mutants with altered metal-binding properties revealed that, despite both Mn
2+
and Zn
2+
being essential metals, maximal growth inhibition of multiple bacterial pathogens requires Mn
2+
sequestration. These data establish the importance of Mn
2+
sequestration in defense against infection, explain the broad-spectrum antimicrobial activity of CP relative to other S100 proteins, and clarify the impact of metal depletion on the innate immune response to infection.
MOZ increases p53 acetylation and premature senescence through its complex formation with PML
Authors: Rokudai Susumu , Laptenko Oleg , Arnal Suzzette M. , Taya Yoichi , Kitabayashi Issay , Prives Carol
Published: February 2013

Monocytic leukemia zinc finger (MOZ)/KAT6A is a MOZ, Ybf2/Sas3, Sas2, Tip60 (MYST)-type histone acetyltransferase that functions as a coactivator for acute myeloid leukemia 1 protein (AML1)- and Ets family transcription factor PU.1-dependent transcription. We previously reported that MOZ directly interacts with p53 and is essential for p53-dependent selective regulation of p21 expression. We show here that MOZ is an acetyltransferase of p53 at K120 and K382 and colocalizes with p53 in promyelocytic leukemia (PML) nuclear bodies following cellular stress. The MOZ–PML–p53 interaction enhances MOZ-mediated acetylation of p53, and this ternary complex enhances p53-dependent p21 expression. Moreover, we identified an Akt/protein kinase B recognition sequence in the PML-binding domain of MOZ protein. Akt-mediated phosphorylation of MOZ at T369 has a negative effect on complex formation between PML and MOZ. As a result of PML-mediated suppression of Akt, the increased PML–MOZ interaction enhances p21 expression and induces p53-dependent premature senescence upon forced PML expression. Our research demonstrates that MOZ controls p53 acetylation and transcriptional activity via association with PML.
Wnt and CDK-1 regulate cortical release of WRM-1/β-catenin to control cell division orientation in early
Caenorhabditis elegans
embryos
Authors: Kim Soyoung , Ishidate Takao , Sharma Rita , Soto Martha C. , Conte Darryl , Mello Craig C. , Shirayama Masaki
Published: February 2013

Significance

Cellular asymmetry, or polarity, is essential for development and tissue homeostasis. In
Caenorhabditis elegans
, the conserved Wnt signal transduction pathway orients the cell division axis and polarizes the EMS blastomere to promote endoderm fate. This work provides a mechanism for how the Wnt/β-catenin pathway integrates spatial and temporal cues important for the cell division axis. We show that CDK-1 phosphorylates and promotes the release of cortical β-catenin, which brings Wnt signaling under cell cycle control and facilitates spindle rotation. Cell cycle control of developmental decisions may be particularly important in embryos or tissues that undergo rapid cell divisions and patterning.
Colony-forming cells in the adult mouse pancreas are expandable in Matrigel and form endocrine/acinar colonies in laminin hydrogel
Authors: Jin Liang , Feng Tao , Shih Hung Ping , Zerda Ricardo , Luo Angela , Hsu Jasper , Mahdavi Alborz , Sander Maike , Tirrell David A. , Riggs Arthur D. , Ku Hsun Teresa
Published: February 2013

The study of hematopoietic colony-forming units using semisolid culture media has greatly advanced the knowledge of hematopoiesis. Here we report that similar methods can be used to study pancreatic colony-forming units. We have developed two pancreatic colony assays that enable quantitative and functional analyses of progenitor-like cells isolated from dissociated adult (2–4 mo old) murine pancreas. We find that a methylcellulose-based semisolid medium containing Matrigel allows growth of duct-like “Ring/Dense” colonies from a rare (∼1%) population of total pancreatic single cells. With the addition of roof plate-specific spondin 1, a wingless-int agonist, Ring/Dense colony-forming cells can be expanded more than 100,000-fold when serially dissociated and replated in the presence of Matrigel. When cells grown in Matrigel are then transferred to a Matrigel-free semisolid medium with a unique laminin-based hydrogel, some cells grow and differentiate into another type of colony, which we name “Endocrine/Acinar.” These Endocrine/Acinar colonies are comprised mostly of endocrine- and acinar-like cells, as ascertained by RNA expression analysis, immunohistochemistry, and electron microscopy. Most Endocrine/Acinar colonies contain beta-like cells that secrete insulin/C-peptide in response toD-glucose and theophylline. These results demonstrate robust self-renewal and differentiation of adult Ring/Dense colony-forming units in vitro and suggest an approach to producing beta-like cells for cell replacement of type 1 diabetes. The methods described, which include microfluidic expression analysis of single cells and colonies, should also advance study of pancreas development and pancreatic progenitor cells.
Recruitment Dynamics of Age‐0 Yellow Perch in a Drowned River Mouth Lake: Assessing Synchrony with Nearshore Lake Michigan
Authors: Janetski David J. , Ruetz Carl R. , Bhagat Yakuta , Clapp David F.
Published: February 2013

We assessed recruitment dynamics of juvenile Yellow Perch Perca flavescens in coastal habitats of eastern Lake Michigan. To investigate recruitment patterns and associations with environmental factors in a coastal drowned river mouth (DRM) lake, we sampled juvenile Yellow Perch seasonally in Muskegon Lake, Michigan, during 2003–2011. We also sampled three nearshore sites in Lake Michigan each fall to evaluate synchrony between the DRM lake and nearshore habitat. In Muskegon Lake, age‐0 Yellow Perch CPUE during fall was high in 2005 and 2007; moderate in 2008, 2010, and 2011; and low in other years. Fall CPUE (age 0) was positively associated with CPUE in the next spring (age 1; slope = 0.98; R2 = 0.95), which we attribute to high overwinter survival. Fall CPUE of age‐0 Yellow Perch showed a positive relationship with June air temperature (R2 = 0.76), suggesting that warm conditions at early larval stages positively influence recruitment of juveniles. Juvenile recruitment in Muskegon Lake was not synchronized with juvenile recruitment in nearshore Lake Michigan. The lack of synchrony may be an indication that (1) age‐0 Yellow Perch recruitment in DRM lakes and Lake Michigan are influenced by different environmental controls and (2) dispersal between the two habitats does not strongly affect age‐0 recruitment dynamics.
Coercive Measures in Forensic Settings: Findings from the Literature
Authors: Hui Ada , Middleton Hugh , Völlm Birgit
Published: February 2013

The use of coercive measures, namely restraint, seclusion and involuntary medication, remain controversial methods of practice within forensic psychiatry. Ethical and moral debates surrounding the use of coercive measures are compounded by the need to balance care, safety, and security. Despite such tensions, limited research has been conducted in this area. This paper examines the prevalence of coercive measures and factors associated with their use specifically within forensic psychiatry. A systematic review was conducted and fifteen empirical studies were identified, each examining the use of coercive measures in forensic inpatient psychiatry, reported in papers published between January 1980 and January 2012. Findings suggest that patients who are younger or newly admitted tend to be secluded most often. Findings relating to gender, ethnicity and patient diagnoses, however, are equivocal. Patients tend to perceive experiences of coercive measures negatively. Staff perceptions however, appear to be determined by their role in governing or practicing coercive interventions. Findings are discussed in light of variations in hospital settings, policies and sociocultural traditions. While the uses of coercive measures appear to be influenced by a combination of all patient, staff, and environmental factors, further research is required to explore each of these aspects in greater detail.
Fearless Dominance and Self-Centered Impulsivity Interact to Predict Predatory Aggression among Forensic Psychiatric Inpatients
Authors: Smith ShannonToney , Edens JohnF. , McDermott BarbaraE.
Published: February 2013

Recent research has begun to investigate the relationship between the Psychopathic Personality Inventory-Revised (PPI-R; Lilienfeld & Widows, 2005) and its primary subscales, Fearless Dominance (FD) and Self-Centered Impulsivity (SCI), and violent behavior. In this follow-up study, we examined the PPI-R subscales’ prospective relationship with predatory, impulsive and psychosis-motivated aggression in an inpatient forensic psychiatric facility ( N = 200). FD and SCI each modestly predicted predatory aggression, and SCI was also modestly associated with any form of aggression. Neither subscale predicted impulsive or psychotic aggression. The statistical interaction between FD and SCI significantly improved the prediction of predatory aggression beyond the individual subscales, indicating that those high on both constructs were particularly at risk to engage in such conduct. Moreover, this interactive effect continued to predict predatory aggression even after controlling for the predictive utility of the Psychopathy Checklist-Revised (Hare, 2003).
Development of a Nested Quantitative Real-Time PCR for DetectingPhytophthora cinnamomiinPersea americanaRootstocks
Authors: Engelbrecht J. , Duong T. A. , van den Berg N.
Published: February 2013

Phytophthora cinnamomi causes Phytophthora root rot (PRR) in avocado (Persea americana), an important disease that causes severe economic losses to the avocado industry globally. To date, no PRR-resistant avocado rootstock variety has been discovered, although certain rootstock varieties have been shown to be more tolerant than others. In this study, we developed an accurate, low cost assay for in planta quantification of P. cinnamomi to evaluate disease tolerance. A nested real-time polymerase chain reaction assay was developed to sensitively detect pathogen DNA in plant tissues. Root samples from a highly tolerant (Dusa) and less tolerant (R0.12) rootstock were collected at 0, 3, 7, 14, and 21 days after inoculation with P. cinnamomi and used for pathogen quantification. Nested primers developed in this study were specific and sensitive and could detect P. cinnamomi in root tissues. The amount of P. cinnamomi quantified in roots was significantly higher in the less-tolerant R0.12 plants when compared with the highly tolerant Dusa plants at all time points. This study has confirmed the known status of disease tolerance of Dusa and R0.12 avocado rootstocks in a quantitative manner and provides a reliable molecular tool to assist with industry breeding programs for the selection of PRR-resistant avocado rootstock varieties.
Effects of Frequency of “Extreme” Temperature Highs on Development of Soybean Rust
Authors: Bonde M. R. , Nester S. E. , Berner D. K.
Published: February 2013

Previously, we hypothesized that summer “extreme” diurnal temperature highs in the southeastern United States were responsible for the yearly absence or delay of soybean rust development until fall. Utilizing temperature-controlled growth chambers, a diurnal temperature pattern of 33°C high and 20°C low reduced urediniospore production by 81%. However, that study did not consider the influence of frequency of extreme temperatures on soybean rust. We now report that a temperature high of 35°C for 1 h on three consecutive days, initiated 15 days after inoculation, when lesions had formed, reduced urediniospore production by 50% and required 9 to 12 days for sporulation to resume once the extreme temperature highs ceased. Furthermore, three consecutive days in which the temperature high was 37°C, beginning immediately after inoculation and subsequent dew period, reduced lesion numbers by 60%. The combined effects of reduced numbers of lesions and urediniospores per lesion caused by extreme temperature highs can account for observed absence or delay of soybean rust development in the southeastern United States until fall. A comparison of frequency of extreme temperature highs with numbers of counties reporting presence of soybean rust from 2005 to 2012 verified that extreme temperature highs may be largely responsible for absence or delay of soybean rust development. This is the first report showing the effect of frequency of extreme temperature highs on development of soybean rust. Because the south-to-north progression of soybean rust is required for the disease to occur in the major soybean-production regions of the United States, temperatures in the southeastern United States have a major effect on the entire U.S. soybean industry.
Cervical Posttraumatic Unilateral Locked Facets
Authors: Piccirilli Manolo , Liberati Chiara , Santoro Giorgio , Santoro Antonio
Published: February 2013

Study Design:

Radiographic and clinical analysis.

Objective:

Review author’s experience with anterior discectomy, interbody fusion, and anterior cervical plating in 33 patients with posttraumatic unilateral cervical locked facets.

Summary of Background Data:

Unilateral cervical locked facet syndrome is a relatively uncommon injury that often is misdiagnosed and therefore subject to a dangerous delay in surgery. Management of this trauma is controversial.

Materials and Methods:

Thirty-three patients with radiologically proven diagnosis of postraumatic unilateral cervical locked facets were treated by skull traction and surgical operation from January 2005 to December 2009. All patients preoperatively were assessed for neurological examination and underwent x-rays, magnetic resonance imaging, and computed tomography evaluation of the cervical spine.

Results:

The unilateral locked facet level was C4–C5 in 13 patients, C5–C6 in 10, C6–C7 in 8, and C3–C4 in 2 patients. After closed reduction attempt with Crutchfield system, the correct alignment was achieved in 30 patients, who underwent anterior discectomy with cage, interbody fusion, and anterior cervical plating. In 3 patients there was an overdistraction and therefore a closed reduction was not possible, so they were firstly operated by posterior approach with opened reduction of the facets, lateral mass screws, and posterolateral fusion. In 2 of these patients there was an anterior fragment of the disk in the canal, so was also performed an anterior approach with discectomy, cage, and plating. There were no surgery-related complications. Postoperative neurological status was unchanged in the 3 patients with tetraplegia and improved in 8 of the 10 patients with radiculopathy. Fusion was obtained in all patients, as showed in the clinical and radiologic follow-up.

Conclusions:

The authors conclude that an anterior approach provides a safe and effective alternative for the treatment of patients with posttraumatic unilateral cervical locked facet, when preoperatively the cervical alignment of the dislocation is achieved with a closed reduction.
Radiographic Adjacent Segment Degeneration at 5 Years After L4/5 Posterior Lumbar Interbody Fusion With Pedicle Screw Instrumentation
Authors: Imagama Shiro , Kawakami Noriaki , Matsubara Yuji , Tsuji Taichi , Ohara Tetsuya , Katayama Yoshito , Ishiguro Naoki , Kanemura Tokumi
Published: February 2013

Study Design:

Retrospective clinical study.

Objective:

To investigate adjacent segment degeneration (ASD) at 5 years after L4/5 posterior lumbar interbody fusion with pedicle screw instrumentation and L4/5 decompression surgery using plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI), with the evaluation of annual changes on MRI.

Summary of Background Data:

Methods of evaluation have been inconsistent among studies of ASD. There is no report that ASD in the lumbar spine after posterior lumbar interbody fusion at the same level is thoroughly evaluated on radiographs, CT, annual MRI changes, and the impact of decompression procedures.

Methods:

ASD was evaluated in 52 patients. Disk height, vertebral slip, intervertebral angle, and intervertebral range of motion were examined on plain radiographs. Facet joint degeneration on CT and disk degradation and spinal stenosis on MRI were classified into categories, and facet sagittalization and tropism were measured on CT. The incidence of ASD was compared between the decompression procedures.

Results:

The radiographic changes observed in the study were defined as radiographic ASD (R-ASD) without reoperation, as no patient required reoperation. R-ASD was rarely detected by radiography. The incidences of facet joint degeneration, MRI-detected disk degeneration, and spinal stenosis at the L3/4 and L5/S1 levels were 21% and 23%, 27% and 17%, and 35% and 4%, respectively. Progressive disk degeneration at L3/4 was found significantly more frequently in patients with aggravation of facet degeneration (P<0.01); however, the severities of preoperative facet degeneration, facet sagittalization, and tropism were not associated with progressive disk degeneration or spinal stenosis. In annual MRI, most R-ASD cases were detected within 3 years after surgery. Patients who underwent L4 total laminectomy had significantly more frequent R-ASD compared with those who received bilateral fenestration at L4/5 (P<0.01).

Conclusions:

R-ASD was detected more frequently by CT and MRI compared with radiography. Preoperative facet joint degeneration and morphology were not always related to progressive disk degeneration or spinal stenosis. Annual MRI suggested that accelerated degeneration was due to lumbar spine fusion, rather than aging degeneration. Decompression with preservation of posterior connective components is recommended to prevent R-ASD.
The Precise Bending Rod Technique
Authors: Yang Junlin , Huang Zifang , Grevitt Michael , Li Jun , Li Fobao , Yang Jingfan
Published: February 2013

Study Design:

To report a new technique.

Objective:

To introduce a new method of precise correction controlling for ankylosing spondylitis kyphosis.

Summary of Background Data:

The exact angle method is excellent for calculating the pedicle subtraction osteotomy angle but is difficult to perform during surgery. In this study, the precise rod bending technique was proposed as a new method for precise correction controlling for ankylosing spondylitis kyphosis through illustrative cases.

Methods:

A preoperative plan using the exact angle method, with exact osteotomy angle and level determined, was prepared using a whole-spine lateral x-ray film. Then a precise contoured rod imitating the predicted spine correction was obtained using the lateral spine x-ray film that was of the actual size of the trunk. This rod model was disinfected and used for precisely controlling kyphosis correction in ankylosing spondylitis patients with good cervical spine and hip joints.

Results:

Four ankylosing spondylitis kyphosis patients were successfully corrected using the precise bending rod technique. Their mean age was 31 years, the mean operative time was 247 minutes (160–320 min), the mean volume of bleeding was 1482 mL (727–2700 mL), and the average follow-up period was 13.8 months (9–17 mo). All patients regained their sagittal balance (all C7–SSVL≤2 cm). The predicted ostetomy degree was accurate to within 2 degrees compared with the achieved degree at the osteotomy site. No complications occurred during or after surgery.

Conclusions:

The precise rod bending technique is a simple, effective method for precise correction of kyphosis caused by ankylosing spondylitis. The surgical result corresponded to the preoperative planning.
Evolution of displays within the pair bond
Authors: Servedio Maria R. , Price Trevor D. , Lande Russell
Published: February 2013

Although sexual selection is an important cause of display evolution, in socially monogamous species (e.g. many birds), displays continue after formation of the pair bond. Here, we consider that these displays evolve because they stimulate the partner to increase investment in offspring. Our study is motivated by elaborate mutual displays in species that are largely monomorphic and have long-term pair bonds (e.g. the great crested grebe,
Podiceps cristatus
) and by many empirical results evidencing that display manipulation affects parental investment. Using population genetic models, we show that a necessary condition for the permanent establishment of mutual displays in the pair bond is that the benefit of investment by the pair is more than twice that resulting from investment by a single individual. Pre-existing biases to respond to displays by increased investment are a necessary component of display evolution. We also consider examples where one sex (e.g. males) stimulates increased investment in offspring by the other sex. Here, display and additional investment cannot evolve permanently, but can increase and linger at high frequency for a long time before loss. We discuss how such transient effects may lead to the evolution of permanent displays as a result of evolution at additional loci.
Vocal copying of individually distinctive signature whistles in bottlenose dolphins
Authors: King Stephanie L. , Sayigh Laela S. , Wells Randall S. , Fellner Wendi , Janik Vincent M.
Published: February 2013

Vocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal displays, vocal learning also allows signal copying in social interactions. Such copying can function in addressing or labelling selected conspecifics. Most examples of addressing in non-humans come from bird song, where matching occurs in an aggressive context. However, in other animals, addressing with learned signals is very much an affiliative signal. We studied the function of vocal copying in a mammal that shows vocal learning as well as complex cognitive and social behaviour, the bottlenose dolphin (Tursiops truncatus). Copying occurred almost exclusively between close associates such as mother–calf pairs and male alliances during separation and was not followed by aggression. All copies were clearly recognizable as such because copiers consistently modified some acoustic parameters of a signal when copying it. We found no evidence for the use of copying in aggression or deception. This use of vocal copying is similar to its use in human language, where the maintenance of social bonds appears to be more important than the immediate defence of resources.
Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS
Authors: Stingl Katarina , Bartz-Schmidt Karl Ulrich , Besch Dorothea , Braun Angelika , Bruckmann Anna , Gekeler Florian , Greppmaier Udo , Hipp Stephanie , Hörtdörfer Gernot , Kernstock Christoph , Koitschev Assen , Kusnyerik Akos , Sachs Helmut , Schatz Andreas , Stingl Krunoslav T. , Peters Tobias , Wilhelm Barbara , Zrenner Eberhart
Published: February 2013

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm
2
chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s
−1
), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (
n
= 8;
p
< 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant's power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.
A Role forMORE AXILLARY GROWTH1(MAX1) in Evolutionary Diversity in Strigolactone Signaling Upstream ofMAX2
Authors: Challis Richard J. , Hepworth Jo , Mouchel Céline , Waites Richard , Leyser Ottoline
Published: February 2013

Strigolactones (SLs) are carotenoid-derived phytohormones with diverse roles. They are secreted from roots as attractants for arbuscular mycorrhizal fungi and have a wide range of endogenous functions, such as regulation of root and shoot system architecture. To date, six genes associated with SL synthesis and signaling have been molecularly identified using the shoot-branching mutants more axillary growth (max) of Arabidopsis (Arabidopsis thaliana) and dwarf (d) of rice (Oryza sativa). Here, we present a phylogenetic analysis of the MAX/D genes to clarify the relationships of each gene with its wider family and to allow the correlation of events in the evolution of the genes with the evolution of SL function. Our analysis suggests that the notion of a distinct SL pathway is inappropriate. Instead, there may be a diversity of SL-like compounds, the response to which requires a D14/D14-like protein. This ancestral system could have been refined toward distinct ligand-specific pathways channeled through MAX2, the most downstream known component of SL signaling. MAX2 is tightly conserved among land plants and is more diverged from its nearest sister clade than any other SL-related gene, suggesting a pivotal role in the evolution of SL signaling. By contrast, the evidence suggests much greater flexibility upstream of MAX2. The MAX1 gene is a particularly strong candidate for contributing to diversification of inputs upstream of MAX2. Our functional analysis of the MAX1 family demonstrates the early origin of its catalytic function and both redundancy and functional diversification associated with its duplication in angiosperm lineages.
Reprogramming the Phenylpropanoid Metabolism in Seeds of Oilseed Rape by Suppressing the Orthologs ofREDUCED EPIDERMAL FLUORESCENCE1
Authors: Mittasch Juliane , Böttcher Christoph , Frolov Andrej , Strack Dieter , Milkowski Carsten
Published: February 2013

As a result of the phenylpropanoid pathway, many Brassicaceae produce considerable amounts of soluble hydroxycinnamate conjugates, mainly sinapate esters. From oilseed rape (Brassica napus), we cloned two orthologs of the Arabidopsis (Arabidopsis thaliana) gene REDUCED EPIDERMAL FLUORESCENCE1 (REF1) encoding a coniferaldehyde/sinapaldehyde dehydrogenase. The enzyme is involved in the formation of ferulate and sinapate from the corresponding aldehydes, thereby linking lignin and hydroxycinnamate biosynthesis as a potential branch-point enzyme. We used RNA interference to silence REF1 genes in seeds of oilseed rape. Nontargeted metabolite profiling showed that BnREF1-suppressing seeds produced a novel chemotype characterized by reduced levels of sinapate esters, the appearance of conjugated monolignols, dilignols, and trilignols, altered accumulation patterns of kaempferol glycosides, and changes in minor conjugates of caffeate, ferulate, and 5-hydroxyferulate. BnREF1 suppression affected the level of minor sinapate conjugates more severely than that of the major component sinapine. Mapping of the changed metabolites onto the phenylpropanoid metabolic network revealed partial redirection of metabolic sequences as a major impact of BnREF1 suppression.
Mating success and energetic condition effects driven by terminal investment in territorial males of a short‐lived invertebrate
Authors: González‐Tokman Daniel M. , González‐Santoyo Isaac , Córdoba‐Aguilar Alex
Published: February 2013

The terminal investment hypothesis has two predictions: in the face of an infection (i) mature males will increase investment to traits that increase mating success, while such investments will occur to a less extent in young males; and (ii) physiological costs of resource reallocation will be more severe for infected mature males than for infected young males.

Although these predictions have been tested in long‐lived vertebrates, prior studies have not examined actual resource allocation conflicts. Here, we have tested the above predictions and have investigated the energetic costs of increased mating by old males, using a short‐lived invertebrate, the damselfly Hetaerina americana. Males of this species defend territories as the main way to obtain access to females.

Using groups of infected vs. noninfected males of two different ages, we found that compared to young infected males, mature infected males defended territories for longer, had higher mating success and directed agonistic behaviour to conspecific males more frequently. Despite similar immune responses by mature and young males, infected mature males ended up with less fat reserves compared to infected young males. This suggests that resource allocation conflicts are more severe for mature than for young males.

In general, these results suggest that the terminal investment hypothesis applies in males of short‐lived invertebrates and that a cause of increased mating success for males of advanced ages is reduced energetic stores.
A Comparative Assessment of the Chen et al. and Suchey‐Brooks Pubic Aging Methods on a North American Sample, ,
Authors: Fleischman Julie M.
Published: February 2013

Accurately estimating the age‐at‐death of adult human skeletons is fundamental in forensic anthropology. This study evaluates the accuracy of two pubic bone age estimation methods—Chen et al. and Suchey‐Brooks. Specimens were obtained from a known collection of modern pubic bones curated at the Maricopa County Forensic Science Center in Phoenix, Arizona. A sample of 296 left male pubic bones of European ancestry was statistically evaluated via bias, absolute mean error, and intra‐ and inter‐observer error. Results indicate that the two methods are similar; the Suchey‐Brooks method is the most accurate for aging young adults (error c. 7 years), while the Revised Chen et al. method is most accurate for aging middle‐age adults (error c. 6 years). Thus, the Chen et al. method is an important contribution to forensic anthropology for aging older adult skeletal remains. There are, however, some limitations such as subjectivity and the intricate scoring system of Chen et al. method.
The Utility of the Proximal Epiphysis of the Fifth Metatarsal in Age Estimation
Authors: Davies Catriona M. , Hackman Lucina , Black Sue
Published: February 2013

Radiographs of 277 living individuals were assessed via a numerical scoring system to determine the timing of appearance and degree of fusion between the proximal epiphysis of the fifth metatarsal and its diaphysis. The epiphysis was observed to first appear in females at 8 years and 10 years in males and fuse by 14 years in females and 15 years in males. When assessing the level of agreement of category assignment, inter‐observer agreement was 78% for females and 64% for males whereas intra‐observer agreement was 77% for females and 86.1% for males. These results suggest that the maturation of the proximal epiphysis of the fifth metatarsal may be of value in age estimation in the child and that the scoring system is sufficiently robust to merit continued investigation. Previously this epiphysis has been considered an inconstant feature, but this research confirmed its presence in all individuals studied.