bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecology and management of rodents in no‐till agriculture in Washington, USA
Authors: WITMER Gary , SAYLER Rodney , HUGGINS David , CAPELLI Jason 
Published: October 2007

AbstractNo‐till farming is an important approach to sustainable agriculture because it can conserve soil and water resources. Unfortunately, rodent populations can thrive under no‐till conditions because burrow systems are not disrupted by annual plowing and plant residues build‐up on the surface, providing cover and insulation. This can result in substantial crop damage. We assessed rodent populations, habitat use, food habits, and crop damage in a no‐till cropping system in Washington, USA. We also conducted preliminary trials of methods to reduce rodent populations and crop damage. In the fall, many more rodents were captured in fields with unharvested crops than in fields containing only plant stubble, suggesting that rodents leave fields after crop harvest, providing that suitable habitats are nearby, even when adequate cover is still available in harvested crop fields. By spring, the number of voles captured was much lower relative to fall. Despite this, capture rates were much higher in surrounding permanent grass areas than in crop (barley, wheat, pea) fields, suggesting that these grassy areas serve as refugia for rodents. Furthermore, the permanent grass cover type was the landscape variable most associated with rodent capture rates. In three winter pea fields, rodents removed 5–15% of the pea plants over winter. Examination of stomach contents revealed that voles mainly fed on grain plants in spring, but that their diet was more diversified in fall. Deer mice fed heavily on grain plants in both spring and fall, but also used insects as food. Metal barrier exclosures (9 m × 9 m), extending above and below ground, did not prevent access by rodents. Rodent populations in areas treated with zinc phosphide on grain were comparable to untreated areas 1 year after application of the rodenticide, perhaps because of immigration and recruitment, suggesting that baiting does not provide a long‐term solution to rodent damage in no‐till agricultural fields.
Evaluation of Genetic and Epigenetic Modification in Rapeseed (Brassica napus) Induced by Salt Stress
Authors: Guangyuan Lu , Xiaoming Wu , Biyun Chen , Gao Guizhen , Kun Xu 
Published: October 2007

Abstract Salinity is an important limiting environmental factor for rapeseed production worldwide. In this study, we assessed the extent and pattern of DNA damages caused by salt stress in rapeseed plants. Amplified fragment length polymorphism (AFLP)
analysis revealed dose‐related increases in sequence alterations in plantlets exposed to 10–1 000 mmol/L sodium chloride. In addition, individual plantlets exposed to the same salt concentration showed different AFLP and selected region amplified polymorphism banding patterns. These observations suggested that DNA mutation in response to salt stress was random in the genome and the effect was dose‐dependant. DNA methylation changes in response to salt stress were also evaluated by methylation sensitive amplified polymorphism (MSAP). Three types of MSAP bands were recovered. Type I bands were observed with both isoschizomers Hpa II and Msp I, while type II and type III bands were observed only with Hpa II and Msp I, respectively. Extensive changes in types of MSAP bands after NaCl treatments were observed, including appearance and disappearance of type I, II and III bands, as well as exchanges between either type I and type II or type I and type III bands. An increase of 0.2–17.6% cytosine methylated CCGG sites were detected in plantlets exposed to 10–200 mmol/L salt compared to the control, and these changes included both de novo methylation and demethylation events. Nine methylation related fragments were also recovered and sequenced, and one sharing a high sequence homology with the ethylene responsive element binding factor was identified. These results demonstrated clear DNA genetic and epigenetic alterations in plantlets as a response to salt stress, and these changes may suggest a mechanism for plants adaptation under salt stress.
Activity of Stress‐related Antioxidative Enzymes in the Invasive Plant Crofton Weed (Eupatorium adenophorum)
Authors: Lu Ping , Sang Wei‐Guo , Ma Ke‐Ping 
Published: October 2007

Abstract Crofton weed is an invasive weed in southwestern China. The activities of several antioxidative enzymes involved in plant protection against oxidative stress were assayed to determine physiological aspects of the crofton weed that might render the plant vulnerable to environmental stress. Stresses imposed on crofton weed were heat (progressively increasing temperatures: 25 °C, 30 °C, 35 °C, 38 °C and 42 °C at 24 h intervals), cold (progressively decreasing temperatures: 25 °C, 20 °C, 15 °C, 10 °C and 5 °C at 24 h intervals), and drought (without watering up to 4 days). The three stresses induced oxidative damage as evidenced by an increase in lipid peroxidation. The effect varied with the stress imposed and the length of exposure. The activity of superoxide dismutase (SOD) increased in response to all stresses but was not significantly different from the controls (P < 0.05) when exposed to cold stress. Catalase (CAT) activity decreased in response to heat and drought stress but increased when exposed to cold conditions. Guaiacol peroxidase (POD) and glutathione reductase (GR) activities increased in response to cold and drought but decreased in response to heat stress. The activity of ascorbate peroxidase (APX) responded differently to all three stresses. Monodehydroascorbate reductase (MDHAR) activity decreased in response to heat and drought, and slightly increased in response to the cold stress but was not significantly different from the controls (P < 0.05). The activity of dehydroascorbate reductase (DHAR) increased in response to all three stresses. Taken together, the co‐ordinate increase of the oxygen‐detoxifying enzymes might be more effective to protect crofton weed from the accumulation of oxygen radicals at low temperatures rather than at high temperatures.
Dense-Granule Protein NcGRA7, a New Marker for the Serodiagnosis ofNeospora caninumInfection in Aborting Cows
Authors: Huang Penglong , Liao Min , Zhang Houshuang , Lee Eung-goo , Nishikawa Yoshifumi , Xuan Xuenan 
Published: October 2007

ABSTRACTTo investigate whether the production of an antigen-specific antibody is associated withNeospora caninum-induced bovine abortion, 62 serum samples were tested with an enzyme-linked immunosorbent assay using the recombinant antigens NcSAG1, NcSRS2, and NcGRA7. Our study suggested that NcGRA7 would be a new marker for the serodiagnosis ofN. caninuminfection resulting in abortion.
Rapid Onset of Intestinal Epithelial Barrier Dysfunction in Primary Human Immunodeficiency Virus Infection Is Driven by an Imbalance between Immune Response and Mucosal Repair and Regeneration
Authors: Sankaran Sumathi , George Michael D. , Reay Elizabeth , Guadalupe Moraima , Flamm Jason , Prindiville Thomas , Dandekar Satya 
Published: October 2007

ABSTRACT

Gut-associated lymphoid tissue (GALT) is an early target for human immunodeficiency virus type 1 (HIV-1) infection and is a site for severe CD4
+
T-cell depletion. HIV-associated enteropathy is well-documented in chronic HIV-1 infection. However, the initial host responses to HIV infection in GALT and the early molecular correlates of HIV enteropathogenesis have not been characterized during primary HIV infection. In this study, we provide evidence of viral replication in GALT resident CD4
+
T cells and macrophages in primary-stage patients and identify early patterns of host mucosal responses and changes in the molecular microenvironment through gene expression profiling. High levels of viral replication in GALT and marked CD4
+
T-cell depletion correlated with decreased expression levels of genes regulating epithelial barrier maintenance and digestive/metabolic functions. These changes coincided with a marked increase in the transcription of immune activation-, inflammation-, and apoptosis-associated genes. Our findings indicate that HIV-induced pathogenesis in GALT emerges at both the molecular and cellular levels prior to seroconversion in primary HIV infection, potentially setting the stage for disease progression by impairing the ability to control viral replication and repair and regenerate intestinal mucosal tissues.
Inhibition of Translation by a Short Element in the 5′ Leader of the Herpes Simplex Virus 1 DNA Polymerase Transcript
Authors: Bryant Kevin F. , Coen Donald M. 
Published: October 2007

ABSTRACT

Many viruses regulate gene expression, both globally and specifically, to achieve maximal rates of replication. During herpes simplex virus 1 infection, translation of the DNA polymerase (Pol) catalytic subunit is inefficient relative to other proteins of the same temporal class (D. R. Yager, A. I. Marcy, and D. M. Coen., J. Virol. 64:2217-2225, 1990). To investigate the mechanisms involved in the inefficient translation of Pol and to determine whether this inefficient translation could affect viral replication, we performed a mutagenic analysis of the 5′ end of the
pol
transcript. We found that a short sequence (∼55 bases) in the 5′ leader of the transcript is both necessary and sufficient to inhibit translation in rabbit reticulocyte lysates and sufficient to inhibit reporter gene translation in transfected cells. RNase structure mapping experiments indicated that the inhibitory element adopts a structure that contains regions of a double-stranded nature, which may interfere with ribosomal loading and/or scanning. Pol accumulated to ∼2- to 3-fold-higher levels per mRNA in cells infected with a mutant virus containing a deletion of the ∼55-base inhibitory element than in cells infected with a control virus containing this element. Additionally, the mutant virus replicated less efficiently than the control virus. These results suggest that the inhibitory element regulates Pol translation during infection and that its inhibition of Pol translation is beneficial for viral replication.
Herpes Simplex Virus Type 1 Immediate-Early Protein ICP27 Is Required for Efficient Incorporation of ICP0 and ICP4 into Virions
Authors: Sedlackova Lenka , Rice Stephen A. 
Published: October 2007

ABSTRACT

Early in infection, herpes simplex virus type 1 (HSV-1) immediate-early (IE) proteins ICP0 and ICP4 localize to the nucleus, where they stimulate viral transcription. Later in infection, ICP0 and to a lesser extent ICP4 accumulate in the cytoplasm, but their biological role there is unknown. Previously, it was shown that the cytoplasmic localization of ICP0/4 requires the multifunctional IE protein ICP27, which is itself an activator of viral gene expression. Here, we identify a viral ICP27 mutant,
d
3-4, which is unable to efficiently localize ICP0 and ICP4 to the cytoplasm but which otherwise resembles wild-type HSV-1 in its growth and viral gene expression phenotypes. These results genetically separate the function of ICP27 that affects ICP0/4 localization from its other functions, which affect viral growth and gene expression. As both ICP0 and ICP4 are known to be minor virion components, we used
d
3-4 to test the hypothesis that the cytoplasmic localization of these proteins is required for their incorporation into viral particles. Consistent with this conjecture,
d
3-4 virions were found to lack ICP0 in their tegument and to have greatly reduced levels of ICP4. Thus, the cytoplasmic localization of ICP0 and ICP4 appears to be a prerequisite for the assembly of these important transcriptional regulatory proteins into viral particles. Furthermore, our results show that ICP27 plays a previously unrecognized role in determining the composition of HSV-1 virions.
Removal of a Single N-Linked Glycan in Human Immunodeficiency Virus Type 1 gp120 Results in an Enhanced Ability To Induce Neutralizing Antibody Responses
Authors: Li Yun , Cleveland Bradley , Klots Igor , Travis Bruce , Richardson Barbra A. , Anderson David , Montefiori David , Polacino Patricia , Hu Shiu-Lok 
Published: October 2007

ABSTRACTGlycans on human immunodeficiency virus (HIV) envelope protein play an important role in infection and evasion from host immune responses. To examine the role of specific glycans, we introduced single or multiple mutations into potential N-linked glycosylation sites in hypervariable regions (V1 to V3) of theenvgene of HIV type 1 (HIV-1) 89.6. Three mutants tested showed enhanced sensitivity to soluble CD4. Mutant N7 (N197Q) in the carboxy-terminal stem of the V2 loop showed the most pronounced increase in sensitivity to broadly neutralizing antibodies (NtAbs), including those targeting the CD4-binding site (IgG1b12) and the V3 loop (447-52D). This mutant is also sensitive to CD4-induced NtAb 17b in the absence of CD4. Unlike the wild-type (WT) Env, mutant N7 mediates CD4-independent infection in U87-CXCR4 cells. To study the immunogenicity of mutant Env, we immunized pig-tailed macaques with recombinant vaccinia viruses, one expressing SIVmac239 Gag-Pol and the other expressing HIV-1 89.6 Env gp160 in WT or mutant forms. Animals were boosted 14 to 16 months later with simian immunodeficiency virusgagDNA and the cognate gp140 protein before intrarectal challenge with SHIV89.6P-MN. Day-of-challenge sera from animals immunized with mutant N7 Env had significantly higher and broader neutralizing activities than sera from WT Env-immunized animals. Neutralizing activity was observed against SHIV89.6, SHIV89.6P-MN, HIV-1 SF162, and a panel of subtype B primary isolates. Compared to control animals, immunized animals showed significant reduction of plasma viral load and increased survival after challenge, which correlated with prechallenge NtAb titers. These results indicate the potential advantages for glycan modification in vaccine design, although the role of specific glycans requires further examination.
FUNDAMENTAL STRUCTURE OF LOOP QUANTUM GRAVITY
Authors: HAN MUXIN , MA YONGGE , HUANG WEIMING 
Published: October 2007

In the recent twenty years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. The aim of loop quantum gravity is to construct a mathematically rigorous, background independent, non-perturbative quantum theory for a Lorentzian gravitational field on a four-dimensional manifold. In the approach, the principles of quantum mechanics are combined with those of general relativity naturally. Such a combination provides us a picture of, so-called, quantum Riemannian geometry, which is discrete on the fundamental scale. Imposing the quantum constraints in analogy from the classical ones, the quantum dynamics of gravity is being studied as one of the most important issues in loop quantum gravity. On the other hand, the semi-classical analysis is being carried out to test the classical limit of the quantum theory. In this review, the fundamental structure of loop quantum gravity is presented pedagogically. Our main aim is to help non-experts to understand the motivations, basic structures, as well as general results. It may also be beneficial to practitioners to gain insights from different perspectives on the theory. We will focus on the theoretical framework itself, rather than its applications, and do our best to write it in modern and precise langauge while keeping the presentation accessible for beginners. After reviewing the classical connection dynamical formalism of general relativity, as a foundation, the construction of the kinematical Ashtekar–Isham–Lewandowski representation is introduced in the content of quantum kinematics. The algebraic structure of quantum kinematics is also discussed. In the content of quantum dynamics, we mainly introduce the construction of a Hamiltonian constraint operator and the master constraint project. At last, some applications and recent advances are outlined. It should be noted that this strategy of quantizing gravity can also be extended to obtain other background-independent quantum gauge theories. There is no divergence within this background-independent and diffeomorphism-invariant quantization program of matter coupled to gravity.
Neural Correlates of Verb Argument Structure Processing
Authors: Thompson Cynthia K. , Bonakdarpour Borna , Fix Stephen C. , Blumenfeld Henrike K. , Parrish Todd B. , Gitelman Darren R. , Mesulam M.-Marsel 
Published: October 2007

AbstractNeuroimaging and lesion studies suggest that processing of word classes, such as verbs and nouns, is associated with distinct neural mechanisms. Such studies also suggest that subcategories within these broad word class categories are differentially processed in the brain. Within the class of verbs, argument structure provides one linguistic dimension that distinguishes among verb exemplars, with some requiring more complex argument structure entries than others. This study examined the neural instantiation of verbs by argument structure complexity: one-, two-, and three-argument verbs. Stimuli of each type, along with nouns and pseudowords, were presented for lexical decision using an event-related functional magnetic resonance imaging design. Results for 14 young normal participants indicated largely overlapping activation maps for verbs and nouns, with no areas of significant activation for verbs compared to nouns, or vice versa. Pseudowords also engaged neural tissue overlapping with that for both word classes, with more widespread activation noted in visual, motor, and peri-sylvian regions. Examination of verbs by argument structure revealed activation of the supramarginal and angular gyri, limited to the left hemisphere only when verbs with two obligatory arguments were compared to verbs with a single argument. However, bilateral activation was noted when both two- and three-argument verbs were compared to one-argument verbs. These findings suggest that posterior peri-sylvian regions are engaged for processing argument structure information associated with verbs, with increasing neural tissue in the inferior parietal region associated with increasing argument structure complexity. These findings are consistent with processing accounts, which suggest that these regions are crucial for semantic integration.
Temporal Characteristics of Top-Down Modulations during Working Memory Maintenance: An Event-related Potential Study of the N170 Component
Authors: Sreenivasan Kartik K. , Katz Jennifer , Jha Amishi P. 
Published: October 2007

Abstract
We investigated the top-down influence of working memory (WM) maintenance on feedforward perceptual processing within occipito-temporal face processing structures. During event-related potential (ERP) recordings, subjects performed a delayed-recognition task requiring WM maintenance of faces or houses. The face-sensitive N170 component elicited by delay-spanning task-irrelevant grayscale noise probes was examined. If early feedforward perceptual activity is biased by maintenance requirements, the N170 ERP component elicited by probes should have a greater N170 amplitude response during face relative to house WM trials. Consistent with this prediction, N170 elicited by probes presented at the beginning, middle, and end of the delay interval was greater in amplitude during face relative to house WM. Thus, these results suggest that WM maintenance demands may modulate early feedforward perceptual processing for the entirety of the delay duration. We argue based on these results that temporally early biasing of domain-specific perceptual processing may be a critical mechanism by which WM maintenance is achieved.
Neural Substrates of Contextual Interference during Motor Learning Support a Model of Active Preparation
Authors: Cross Emily S. , Schmitt Paul J. , Grafton Scott T. 
Published: October 2007

Abstract
When individuals acquire new skills, initial performance is typically better and tasks are judged to be easier when the tasks are segregated and practiced by block, compared to when different tasks are randomly intermixed in practice. However, subsequent skill retention is better for a randomly practiced group, an effect known as contextual interference (CI). The present study examined the neural substrates of CI using functional magnetic resonance imaging (fMRI). Individuals learned a set of three 4-element sequences with the left hand according to a block or random practice schedule. Behavioral retest for skill retention confirmed the presence of a typical CI effect with the random group outperforming the block group. Using a go/no-go fMRI paradigm, sequence preparation during the premovement study period was separated from movement execution. Imaging data for the two groups were compared for the first 1/3 and final 1/3 of training trials. Toward the end of training, behavioral performance between the two groups was similar, although the random group would later display a performance advantage on retention testing. During study time, the random group showed greater activity in sensorimotor and premotor regions compared to the block group. These areas are associated with motor preparation, sequencing, and response selection. This pattern of recruitment is consistent with the hypothesis that CI benefits in a sequencing task are due to improved capacity to actively prepare motor responses.
The Contribution of the Inferior Parietal Lobe to Auditory Spatial Working Memory
Authors: Alain Claude , He Yu , Grady Cheryl 
Published: October 2007

Abstract
There is strong evidence for dissociable “what” and “where” pathways in the auditory system, but considerable debate remains regarding the functional role of these pathways. The sensory-motor account of spatial processing posits that the dorsal brain regions (e.g., inferior parietal lobule, IPL) mediate sensory-motor integration required during “where” responding. An alternative account suggests that the IPL plays an important role in monitoring sound location. To test these two models, we used a mixed-block and event-related functional magnetic resonance imaging (fMRI) design in which participants responded to occasional repetitions in either sound location (“where” task) or semantic category (“what” task). The fMRI data were analyzed with the general linear model using separate regressors for representing sustained and transient activity in both listening conditions. This analysis revealed more sustained activity in right dorsal brain regions, including the IPL and superior frontal sulcus, during the location than during the category task, after accounting for transient activity related to target detection and the motor response. Conversely, we found greater sustained activity in the left superior temporal gyrus and left inferior frontal gyrus during the category task compared to the location task. Transient target-related activity in both tasks was associated with enhanced signal in the left pre- and postcentral gyrus, prefrontal cortex and bilateral IPL. These results suggest dual roles for the right IPL in auditory working memory—one involved in monitoring and updating sound location independent of motor responding, and another that underlies the integration of sensory and motor functions.