bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathophysiology of Acute Pancreatitis: Potential Application from Experimental Models and Human Medicine to Dogs
Authors: Mansfield Caroline
Published: June 2012

The cellular events leading to pancreatitis have been studied extensively in experimental models. Understanding the cellular events and inciting causes of the multisystem inflammatory cascades that are activated with this disease is of vital importance to advance diagnosis and treatment of this condition. Unfortunately, the pathophysiology of pancreatitis in dogs is not well understood, and extrapolation from experimental and human medicine is necessary. The interplay of the inflammatory cascades (kinin, complement, cytokine) is extremely complex in both initiating leukocyte migration and perpetuating disease. Recently, nitric oxide (NO) and altered microcirculation of the pancreas have been proposed as major initiators of inflammation. In addition, the role of the gut is becoming increasingly explored as a cause of oxidative stress and potentiation of systemic inflammation in pancreatitis.
Reticular formation responses to magnetic brain stimulation of primary motor cortex
Authors: Fisher Karen M. , Zaaimi Boubker , Baker Stuart N.
Published: June 2012

Key points

Transcranial magnetic stimulation (TMS) is a popular technique for the non‐invasive investigation of motor function and is often assumed to influence spinal circuits solely via the corticospinal tract.

In anaesthetized monkeys, we observed robust responses to TMS over motor cortex in single units recorded within the brainstem reticular formation.

Short latency responses were consistent with activation of a cortico‐reticular pathway. More powerful later responses seemed to be associated with the click sound produced by the coil on discharge.

Activation of brainstem neurones by sound must be considered as a potential confound during future TMS studies.

TMS might provide an easy, non‐invasive method for activating the motor reticular formation in human subjects.

Abstract  Transcranial magnetic stimulation (TMS) of cerebral cortex is a popular technique for the non‐invasive investigation of motor function. TMS is often assumed to influence spinal circuits solely via the corticospinal tract. We were interested in possible trans‐synaptic effects of cortical TMS on the ponto‐medullary reticular formation in the brainstem, which is the source of the reticulospinal tract and could also generate spinal motor output. We recorded from 210 single units in the reticular formation of three anaesthetized macaque monkeys whilst TMS was performed over primary motor cortex. Short latency responses were observed consistent with activation of a cortico‐reticular pathway. However, we also demonstrated surprisingly powerful responses at longer latency, which often appeared at lower threshold than the earlier effects. These late responses seemed to be generated partly as a consequence of the sound click made by coil discharge, and changed little with coil location. This novel finding has implications for the design of future studies using TMS, as well as suggesting a means of non‐invasively probing an otherwise inaccessible important motor centre.
Consumption of a high‐fat diet, but not regular endurance exercise training, regulates hypothalamic lipid accumulation in mice
Authors: Borg Melissa L. , Omran Simin Fallah , Weir Jacquelyn , Meikle Peter J. , Watt Matthew J.
Published: June 2012

Key points

‘Lipotoxicity’ refers to the excessive accumulation of lipids in non‐adipose tissues that causes cellular dysfunction and, in severe cases, cell death. Lipotoxicity is often present in obesity.

It is unknown whether lipotoxicity occurs in the hypothalamus of the brain, an area involved in the regulation of feeding behaviour and energy balance.

We show that high‐fat feeding results in increased lipid content in the hypothalamus, including triacylglycerol, diacylglycerol and ceramide, which was not reduced with 6 weeks of exercise training.

The obese leptin‐deficient ob/ob mouse fed a chow diet had normal hypothalamic lipid content.

These data show that dietary lipids regulate hypothalamic lipid accumulation, which is not readily reversed by exercise training.

Abstract  Obesity is characterised by increased storage of fatty acids in an expanded adipose tissue mass and in peripheral tissues such as the skeletal muscle and liver, where it is associated with the development of insulin resistance. Insulin resistance also develops in the central nervous system with high‐fat feeding. The capacity for hypothalamic cells to accumulate/store lipids, and the effects of obesity remain undefined. The aims of this study were (1) to examine hypothalamic lipid content in mice with increased dietary fat intake and in obese ob/ob mice fed a low‐fat diet, and (2) to determine whether endurance exercise training could reduce hypothalamic lipid accumulation in high‐fat fed mice. Male C57BL/6 mice were fed a low‐ (LFD) or high‐fat diet (HFD) for 12 weeks; ob/ob mice were maintained on a chow diet. HFD‐exercise (HFD‐ex) mice underwent 12 weeks of high‐fat feeding with 6 weeks of treadmill exercise training (increasing from 30 to 70 min day−1). Hypothalamic lipids were assessed by unbiased mass spectrometry. The HFD increased body mass and hepatic lipid accumulation, and induced glucose intolerance, while the HFD‐ex mice had reduced body weight and improved glucose tolerance. A total of 335 lipid molecular species were identified and quantified. Lipids known to induce insulin resistance, including ceramide (22%↑), diacylglycerol (25%↑), lysophosphatidylcholine (17%↑), cholesterol esters (60%↑) and dihexosylceramide (33%↑), were increased in the hypothalamus of HFD vs. LFD mice. Hypothalamic lipids were unaltered with exercise training and in the ob/ob mice, suggesting that obesity per se does not alter hypothalamic lipids. Overall, hypothalamic lipid accumulation is regulated by dietary lipid content and is refractory to change with endurance exercise training.
KCa channels and epoxyeicosatrienoic acids: major contributors to thermal hyperaemia in human skin
Authors: Brunt Vienna E. , Minson Christopher T.
Published: June 2012

Key points

The increased blood flow associated with local heating of the skin is ∼60% dependent on nitric oxide. The remaining ∼40% is unknown.

Endothelial‐derived hyperpolarizing factors (EDHFs), a class of vasodilators, are known to contribute to increases in blood flow in other vascular beds.

In the present study, we showed the drug tetraethylammonium (which blocks the channels involved in EDHF‐mediated vasodilatation), when given in combination with nitric oxide synthase inhibition, blocked the majority of hyperaemia to local heat, indicating that EDHFs are responsible for the majority of the remaining ∼40% of hyperaemia.

We also showed that about half of the EDHF‐component is attributed to a specific type of EDHF, epoxyeicosatrienoic acid (EET), as evidenced using the cytochrome P450 inhibitor sulfaphenazole.

These findings help further our understanding of the mechanisms behind cutaneous thermal hyperaemia.

Abstract  While it is accepted that NO is responsible for ∼60% of the plateau in cutaneous thermal hyperaemia, a large portion of the response remains unknown. We sought to determine whether the remaining ∼40% could be attributed to EDHF‐mediated activation of KCa channels, and whether the epoxyeicosatrienoic acids (EETs), derived via cytochrome P450, were the predominant EDHF active in the response. Four microdialysis fibres were placed in the forearm skin of 20 subjects. In Protocol 1 (n= 10): (1) Control, (2) NG‐nitro‐l‐arginine methyl ester (l‐NAME), (3) a KCa channel inhibitor, tetraethylammonium (TEA), and (4) TEA +l‐NAME. In Protocol 2 (n= 10): (1) Control, (2) l‐NAME, (3) a cytochrome P450 inhibitor, sulfaphenazole, and (4) sulfaphenazole +l‐NAME. Local heating to 42°C was performed and skin blood flow was measured with laser Doppler flowmetry. Data are presented as the percentage of maximal cutaneous vascular conductance (CVC). All drug sites attenuated plateau CVC from the control site (86 ± 1%) to 79 ± 3% with sulfaphenazole (P= 0.02 from control), 71 ± 3% with TEA (P= 0.01 from control), and further to 38 ± 2% with l‐NAME (P < 0.001 from control, P < 0.001 from TEA). Plateau was largely attenuated with sulfaphenazole +l‐NAME (24 ± 2%; P= 0.002 from l‐NAME), and nearly abolished with l‐NAME + TEA (13 ± 2%; P= 0.001 from sulfaphenazole +l‐NAME), which was not different from baseline (P= 0.14). Furthermore, the initial peak was just 17 ± 2% with TEA +l‐NAME (P < 0.001 from l‐NAME). These data suggest EDHFs are responsible for a large portion of initial peak and the remaining 40% of the plateau phase, as administration of TEA in combination with l‐NAME abolished the majority of hyperaemia. These data also suggest EETs contribute to about half of the EDHF response.
Underwater Implosion of Cylindrical Metal Tubes
Authors: Turner Stephen E. , Ambrico Joseph M.
Published: June 2012

The basic physics of the underwater implosion of metal tubes is studied using small scale experiments and finite element simulations. A series of underwater implosion experiments have been conducted with thin-wall aluminum alloy 6061-T6 tubes. The nominal tube dimensions are 2.54 cm outside diameter and 30.48 cm length. Two cylinders collapsed at their natural buckling pressure of 6895 kPa gauge pressure (1000 psig). Two additional cylinders were caused to implode at 6205 kPa gauge pressure (900 psig) using an initiator mechanism. Each of the four cylinders failed with a mode 2 shape (collapsed shape is flat with two lobes). The near field pressure time-history in the water is measured at a radial distance of 10.16 cm (4in.) from the centerline at three points along the cylinder's length. The pressure time-histories show very similar behavior between the cylinders which buckled naturally and those which were mechanically initiated at 90% of the buckling pressure. To aid in understanding the physical implosion phenomena, a computational model is developed with a fluid-structure-interaction finite element code (DYSMAS). This model is validated against the experimental data, and it is used to explain the features of the implosion pressure pulse and how it is physically created.
The Temporal Evolution of Buckling in a Dynamically Impacted Column
Authors: Ji Wooseok , Waas Anthony M.
Published: June 2012

The time-dependent progressive evolution of transverse displacements of an axially impacted, slender, geometrically imperfect, column is studied here. The analysis is concerned with evaluating the time-history associated with the evolution of the buckling response as a function of the initial geometric imperfection amplitude. The exact solution of the axial stress wave propagation is employed to study the physics of the buckling response with the nonuniform axial strain distribution varying in time and space. The responses of axially impacted columns are examined in light of past experimental results and associated numerical solutions. Results in the present paper are limited to elastic column behavior.
The Stomatopod Dactyl Club: A Formidable Damage-Tolerant Biological Hammer
Authors: Weaver James C. , Milliron Garrett W. , Miserez Ali , Evans-Lutterodt Kenneth , Herrera Steven , Gallana Isaias , Mershon William J. , Swanson Brook , Zavattieri Pablo , DiMasi Elaine , Kisailus David
Published: June 2012

Hammering Home the Lesson

Stomatopods are marine crustaceans that use hammerlike claws for defense and to attack their prey. The claws undergo repeated high-velocity and high-force impacts.

Weaver
et al.

(p.
1275
; see the Perspective by

Tanner

) used a variety of techniques to examine the structure, mechanical behavior, and toughening mechanisms of the claw of the Peacock Mantis shrimp. The claw's composite structure is optimized for toughness, which helps to prevent the complete failure that might arise from the claw's repetitive hammering.
Room-Temperature Quantum Bit Memory Exceeding One Second
Authors: Maurer P. C. , Kucsko G. , Latta C. , Jiang L. , Yao N. Y. , Bennett S. D. , Pastawski F. , Hunger D. , Chisholm N. , Markham M. , Twitchen D. J. , Cirac J. I. , Lukin M. D.
Published: June 2012

Extending Quantum Memory

Practical applications in quantum communication and quantum computation require the building blocks—quantum bits and quantum memory—to be sufficiently robust and long-lived to allow for manipulation and storage (see the Perspective by

Boehme and McCarney

).

Steger
et al.

(p.
1280
) demonstrate that the nuclear spins of
31
P impurities in an almost isotopically pure sample of
28
Si can have a coherence time of as long as 192 seconds at a temperature of ∼1.7 K. In diamond at room temperature,

Maurer
et al.

(p.
1283
) show that a spin-based qubit system comprised of an isotopic impurity (
13
C) in the vicinity of a color defect (a nitrogen-vacancy center) could be manipulated to have a coherence time exceeding one second. Such lifetimes promise to make spin-based architectures feasible building blocks for quantum information science.
Global Honey Bee Viral Landscape Altered by a Parasitic Mite
Authors: Martin Stephen J. , Highfield Andrea C. , Brettell Laura , Villalobos Ethel M. , Budge Giles E. , Powell Michelle , Nikaido Scott , Schroeder Declan C.
Published: June 2012

Honey Bees Beware of the Mite

The emergence of a virulent form of a viral disease that has long been associated with the world-wide death of honey bees has occurred in the Hawaiian archipelago.

Martin
et al.

(p.
1304
) exploited this unique situation to study the mechanisms behind the emergence. Honey bee populations have long been established on the isolated Hawaiian Islands but only recently have some islands become infested with the
Varroa
mite. This mite has selected for a single viral pathogen-deformed wing virus among the honey bee population, with the appearance of a single dominant virus strain, which has now spread worldwide. Thus, a normally benign viral pathogen has become one of the most widely distributed and contagious insect viruses on the planet.
Actin Network Architecture Can Determine Myosin Motor Activity
Authors: Reymann Anne-Cécile , Boujemaa-Paterski Rajaa , Martiel Jean-Louis , Guérin Christophe , Cao Wenxiang , Chin Harvey F. , De La Cruz Enrique M. , Théry Manuel , Blanchoin Laurent
Published: June 2012

Actin Up

Actomyosin interactions lie at the heart of fundamental cellular processes—including morphogenesis, establishment of polarity, and overall motility—but the general principles driving the spatiotempotal orchestration of these interactions have remained elusive. Working in vitro, using micropatterned substrates,

Reymann
et al.

(p.
1310
) demonstrate that myosins can use a “selection orientation” mechanism to pull selectively on actin filaments, contract the actin network and disassemble it, or walk on the filaments, align them, allow their growth, and control filament orientation.
Vitamin K
2
Takes Charge
Authors: Bhalerao Sheetal , Clandinin Thomas R.
Published: June 2012

A vitamin carries electrons in the mitochondrial transport chain.
Europe Mulls Plans to Boost Research in Poorer Regions
Authors: Laursen Lucas
Published: June 2012

Europe's next elite research centers could be built in the poor regions in the south and east of the continent but managed by prestigious research institutions in wealthier countries.
Do Sports Events Give Microbes a Chance to Score?
Authors: Kupferschmidt Kai
Published: June 2012

Mass gatherings can be a hub for spreading diseases, but studies suggest the risks, though real, are surprisingly small.
From Soldiers to Veterans, Good Health to Bad
Authors: Kean Sam
Published: June 2012

Hoping to improve medical care, the U.S. military has been keeping tabs on soldiers' environmental exposures and mental problems; the results are mixed.
Crossover Immune Cells Blur the Boundaries
Authors: Leslie Mitch
Published: June 2012

Researchers have discovered novel cells that take on roles of T cells and might worsen immune diseases.
Taking Stock of the Human Microbiome and Disease
Authors: Balter Michael
Published: June 2012

Programs that helped jump-start the microbiome field have yet to come up with the best way to follow up on their discoveries.
My Microbiome and Me
Authors: Hvistendahl Mara
Published: June 2012

Zhao Liping combines traditional Chinese medicine and studies of gut microbes to understand and fight obesity.
LIFE SCIENCE TECHNOLOGIES: Digital Imaging Sees Results
Authors: Dove Alan
Published: June 2012

Photography has been a fundamental part of biology for more than a century, but a new generation of digital imaging technologies is revolutionizing the way life scientists capture and analyze visual data.
Differential Detection of Avian Oncogenic Viruses in Poultry Layer Farms and Turkeys by Use of Multiplex PCR
Authors: Gopal Sathish , Manoharan Parthiban , Kathaperumal Kumanan , Chidambaram Balachandran , Divya Kurunchi C.
Published: June 2012

Avian oncogenic viruses include Marek's disease virus (MDV), a highly contagious herpesvirus, as well as retroviruses such as avian leukosis virus (ALV) subgroups A to J and reticuloendotheliosis virus (REV). In this study, we examined the incidence of these viruses in suspected samples collected from poultry layer farms of South India, mainly in the Namakkal district of Tamil Nadu, a highly dense poultry-growing area in India. The histopathology-positive tissue sections were identified and further confirmed by immunohistochemistry using virus-specific antibodies. The viruses belonging to all 3 groups (MDV, ALV, and REV) were isolated in a cell culture system and confirmed by immunofluorescence using virus-specific antibodies. PCR appeared to be the method of choice for rapid and accurate diagnosis of these viruses. The multiplex PCR primers specific to MDV, ALV, REV, and chicken DNA were designed for rapid differential diagnosis. The specificity of the primers was checked by amplification of DNA from virus-infected cell culture in comparison with uninfected samples, and sensitivity was evaluated by calculating the minimum copy number at which amplification occurs in the cloned PCR products. The sequences of the amplicons were compared by BLAST analysis. PCR tests demonstrated the presence of single, dual, or triple viruses in some of the samples. Of 169 samples screened by multiplex PCR, 9 samples were positive for MDV, 17 samples were positive for ALV, 12 samples were positive for REV, and 17 samples were positive for both ALV and REV. Three samples were positive for all three viruses. ALV-positive samples were further subjected to subgroup-specific PCR, which gave positive results for subgroups B and D but not for subgroup J. Multiplex PCR appeared to be a useful technique for rapid differential diagnosis of avian oncogenic viruses and detection of multiple infections of avian oncogenic viruses under field conditions.
Novel Approach for Detection of Hepatitis E Virus Infection in German Blood Donors
Authors: Vollmer Tanja , Diekmann Juergen , Johne Reimar , Eberhardt Matthias , Knabbe Cornelius , Dreier Jens
Published: June 2012

The risk of transfusion-transmitted hepatitis E virus (HEV) infections by contaminated blood products remains unknown. In the present study, we evaluated and compared different nucleic acid amplification technique (NAT) methods for the detection of HEV in blood components. Minipools of a total of 16,125 individual blood donors were screened for the presence of HEV RNA using the highly sensitive RealStar HEV RT-PCR kit, revealing a minimum detection limit of 4.66 IU/ml. Thirteen donors were HEV RNA positive (0.08%), and of these donors, only three already showed reactive IgM antibody titers. The detected HEV strains all belonged to genotype 3 and were most closely related to German HEV strains from wild boars and pigs as well as from human hepatitis E cases. Furthermore, HEV RNA and HEV-specific IgM and IgG titers were determined in 136 blood donors with elevated alanine aminotransferase (ALT) levels and in 200 donors without pathological findings. HEV RNA was not detectable, but 8.08% (elevated ALT) and 0.5% (nonelevated ALT) of donors showed reactive HEV IgM titers. The overall seroprevalence rate of HEV IgG amounted to 5.94% (elevated ALT, 5.88%; nonelevated ALT, 6.0%). The clinical relevance of transfusion-associated hepatitis E infection still requires further investigation. However, in connection with raising concerns regarding blood safety, our NAT method provides a sensitive possibility for HEV testing.
Cell Culture-Adaptive Mutations Promote Viral Protein-Protein Interactions and Morphogenesis of Infectious Hepatitis C Virus
Authors: Jiang Jieyun , Luo Guangxiang
Published: June 2012

Recent genetic studies suggested that viral nonstructural (NS) proteins play important roles in morphogenesis of flaviviruses, particularly hepatitis C virus (HCV). Adaptive and compensatory mutations occurring in different NS proteins were demonstrated to promote HCV production in cell culture. However, the underlying molecular mechanism of NS proteins in HCV morphogenesis is poorly understood. We have isolated a cell culture-adapted HCV of genotype 2a (JFH1) which grew to an infectious titer 3 orders of magnitude higher than that of wild-type virus. Sequence analysis identified a total of 16 amino acid mutations in core (C), E1, NS2, NS3, NS5A, and NS5B, with the majority of mutations clustered in NS5A. Reverse genetic analysis of these mutations individually or in different combinations demonstrated that amino acid mutations in NS2 and NS5A markedly enhanced HCV production. Additionally, mutations in C, E1, NS3, and NS5B synergistically promoted HCV production in the background of NS2 and NS5A mutations. Adaptive mutations in NS5A domains I, II, and III independently enhanced HCV production, suggesting that all three domains of NS5A are important for HCV morphogenesis. More importantly, adaptive mutations greatly enhanced physical interactions among HCV structural and NS proteins, as determined by studies with coimmunoprecipitation and mammalian two-hybrid assays. Collectively, these findings demonstrate that adaptive mutations can enhance specific protein-protein interactions among viral structural and NS proteins and therefore promote the assembly of infectious HCV particles.
Transport to Late Endosomes Is Required for Efficient Reovirus Infection
Authors: Mainou Bernardo A. , Dermody Terence S.
Published: June 2012

Rab GTPases play an essential role in vesicular transport by coordinating the movement of various types of cargo from one cellular compartment to another. Individual Rab GTPases are distributed to specific organelles and thus serve as markers for discrete types of endocytic vesicles. Mammalian reovirus binds to cell surface glycans and junctional adhesion molecule-A (JAM-A) and enters cells by receptor-mediated endocytosis in a process dependent on β1 integrin. Within organelles of the endocytic compartment, reovirus undergoes stepwise disassembly catalyzed by cathepsin proteases, which allows the disassembly intermediate to penetrate endosomal membranes and release the transcriptionally active viral core into the cytoplasm. The pathway used by reovirus to traverse the endocytic compartment is largely unknown. In this study, we found that reovirus particles traffic through early, late, and recycling endosomes during cell entry. After attachment to the cell surface, reovirus particles and JAM-A codistribute into each of these compartments. Transfection of cells with constitutively active and dominant-negative Rab GTPases that affect early and late endosome biogenesis and maturation influenced reovirus infectivity. In contrast, reovirus infectivity was not altered in cells expressing mutant Rab GTPases that affect recycling endosomes. Thus, reovirus virions localize to early, late, and recycling endosomes during entry into host cells, but only those that traverse early and late endosomes yield a productive infection.
ORF7 of Varicella-Zoster Virus Is a Neurotropic Factor
Authors: Selariu Anca , Cheng Tong , Tang Qiyi , Silver Benjamin , Yang Lianwei , Liu Che , Ye Xiangzhong , Markus Amos , Goldstein Ronald S. , Cruz-Cosme Ruth S. , Lin Yanzhen , Wen Lanling , Qian Hongliu , Han Jinle , Dulal Kalpana , Huang Ying , Li Yimin , Xia Ningshao , Zhu Hua
Published: June 2012

Varicella-zoster virus (VZV) is the causative agent of chickenpox and herpes zoster (shingles). After the primary infection, the virus remains latent in sensory ganglia and reactivates upon weakening of the cellular immune system due to various conditions, erupting from sensory neurons and infecting the corresponding skin tissue. The current varicella vaccine is highly attenuated in the skin and yet retains its neurovirulence and may reactivate and damage sensory neurons. The factors involved in neuronal invasion and establishment of latency are still elusive. Previously, we constructed a library of whole-gene deletion mutants carrying a bacterial artificial chromosome sequence and a luciferase marker in order to perform a comprehensive VZV genome functional analysis. Here, screening of dispensable gene deletion mutants in differentiated neuronal cells led to the identification of ORF7 as the first known, likely a main, VZV neurotropic factor. ORF7 is a virion component localized to the Golgi compartment in infected cells, whose deletion causes loss of polykaryon formation in epithelial cell culture. Interestingly, ORF7 deletion completely abolishes viral spread in human nervous tissue
ex vivo
and in an
in vivo
mouse model. This finding adds to our previous report that ORF7 is also a skin-tropic factor. The results of our investigation will not only lead to a better understanding of VZV neurotropism but could also contribute to the development of a neuroattenuated vaccine candidate against shingles or a vector for delivery of other antigens.
Kaposi's Sarcoma-Associated Herpesvirus ORF54/dUTPase Downregulates a Ligand for the NK Activating Receptor NKp44
Authors: Madrid Alexis Spain , Ganem Don
Published: June 2012

Kaposi's sarcoma-associated herpesvirus (KSHV) establishes long-term latent infection in humans and can cause cancers in endothelial and B cells. A functioning immune system is vital for restricting viral proliferation and preventing KSHV-dependent neoplasms. While natural killer (NK) lymphocytes are known to target virus-infected cells for destruction, their importance in the anti-KSHV immune response is not currently understood. Activating receptors on NK cells recognize ligands on target cells, including the uncharacterized ligand(s) for NKp44, termed NKp44L. Here we demonstrate that several NK ligands are affected when KSHV-infected cells are induced to enter the lytic program. We performed a screen of most of the known KSHV genes and found that the product of the ORF54 gene could downregulate NKp44L. The ORF54-encoded protein is a dUTPase; however, dUTPase activity is neither necessary nor sufficient for the downregulation of NKp44L. In addition, we find that ORF54 can also target proteins of the cytokine receptor family and the mechanism of downregulation involves perturbation of membrane protein trafficking. The ORF54-related proteins of other human herpesviruses do not possess this activity, suggesting that the KSHV homolog has evolved a novel immunoregulatory function and that the NKp44-NKp44L signaling pathway contributes to antiviral immunity.
Infectious Endogenous Retroviruses in Cats and Emergence of Recombinant Viruses
Authors: Anai Yukari , Ochi Haruyo , Watanabe Shinya , Nakagawa So , Kawamura Maki , Gojobori Takashi , Nishigaki Kazuo
Published: June 2012

Endogenous retroviruses (ERVs) comprise a significant percentage of the mammalian genome, and it is poorly understood whether they will remain as inactive genomes or emerge as infectious retroviruses. Although several types of ERVs are present in domestic cats, infectious ERVs have not been demonstrated. Here, we report a previously uncharacterized class of endogenous gammaretroviruses, termed ERV-DCs, that is present and hereditary in the domestic cat genome. We have characterized a subset of ERV-DC proviral clones, which are numbered according to their genomic insertions. One of these, ERV-DC10, located in the q12-q21 region on chromosome C1, is an infectious gammaretrovirus capable of infecting a broad range of cells, including human. Our studies indicate that ERV-DC10 entered the genome of domestic cats in the recent past and appeared to translocate to or reintegrate at a distinct locus as infectious ERV-DC18. Insertional polymorphism analysis revealed that 92 of 244 domestic cats had ERV-DC10 on a homozygous or heterozygous locus. ERV-DC-like sequences were found in primate and rodent genomes, suggesting that these ERVs, and recombinant viruses such as RD-114 and BaEV, originated from an ancestor of ERV-DC. We also found that a novel recombinant virus, feline leukemia virus subgroup D (FeLV-D), was generated by ERV-DC
env
transduction into feline leukemia virus in domestic cats. Our results indicate that ERV-DCs behave as donors and/or acceptors in the generation of infectious, recombinant viruses. The presence of such infectious endogenous retroviruses, which could be harmful or beneficial to the host, may affect veterinary medicine and public health.
Structure and Receptor Complexes of the Hemagglutinin from a Highly Pathogenic H7N7 Influenza Virus
Authors: Yang Hua , Carney Paul J. , Donis Ruben O. , Stevens James
Published: June 2012

Recurrence of highly pathogenic avian influenza (HPAI) virus subtype H7 in poultry continues to be a public health concern. In 2003, an HPAI H7N7 outbreak in the Netherlands infected 89 people in close contact with affected poultry and resulted in one fatal case. In previous studies, the virus isolated from this fatal case, A/Netherlands/219/2003 (NL219) caused a lethal infection in mouse models and had increased replication efficiency and a broader tissue distribution than nonlethal isolates from the same outbreak. A mutation which introduces a potential glycosylation site at Asn123 in the NL219 hemagglutinin was postulated to contribute to the pathogenic properties of this virus. To study this further, we have expressed the NL219 hemagglutinin in a baculovirus expression system and performed a structural analysis of the hemagglutinin in complex with avian and human receptor analogs. Glycan microarray and kinetic analysis were performed to compare the receptor binding profile of the wild-type recombinant NL219 HA to a variant with a threonine-to-alanine mutation at position 125, resulting in loss of the glycosylation site at Asn123. The results suggest that the additional glycosylation sequon increases binding affinity to avian-type α2-3-linked sialosides rather than switching to a human-like receptor specificity and highlight the mechanistic diversity of these pathogens, which calls attention to the need for further studies to fully understand the unique properties of these viruses.
Antibody-Dependent Cellular Cytotoxicity against Primary HIV-Infected CD4+T Cells Is Directly Associated with the Magnitude of Surface IgG Binding
Authors: Smalls-Mantey Adjoa , Doria-Rose Nicole , Klein Rachel , Patamawenu Andy , Migueles Stephen A. , Ko Sung-Youl , Hallahan Claire W. , Wong Hing , Liu Bai , You Lijing , Scheid Johannes , Kappes John C. , Ochsenbauer Christina , Nabel Gary J. , Mascola John R. , Connors Mark
Published: June 2012

Antibody (Ab)-dependent cellular cytotoxicity (ADCC) is thought to potentially play a role in vaccine-induced protection from HIV-1. The characteristics of such antibodies remain incompletely understood. Furthermore, correlates between ADCC and HIV-1 immune status are not clearly defined. We screened the sera of 20 HIV-1-positive (HIV-1+) patients for ADCC. Normal human peripheral blood mononuclear cells were used to derive HIV-infected CD4+T cell targets and autologous, freshly isolated, natural killer (NK) cells in a novel assay that measures granzyme B (GrB) and HIV-1-infected CD4+T cell elimination (ICE) by flow cytometry. We observed that complex sera mediated greater levels of ADCC than anti-HIV-1 envelope glycoprotein (Env)-specific monoclonal antibodies and serum-mediated ADCC correlated with the amount of IgG and IgG1 bound to HIV-1-infected CD4+T cells. No correlation between ADCC and viral load, CD4+T cell count, or neutralization of HIV-1SF162or other primary viral isolates was detected. Sera pooled from clade B HIV-1+individuals exhibited breadth in killing targets infected with HIV-1 from clades A/E, B, and C. Taken together, these data suggest that the total amount of IgG bound to an HIV-1-infected cell is an important determinant of ADCC and that polyvalent antigen-specific Abs are required for a robust ADCC response. In addition, Abs elicited by a vaccine formulated with immunogens from a single clade may generate a protective ADCC responsein vivoagainst a variety of HIV-1 species. Increased understanding of the parameters that dictate ADCC against HIV-1-infected cells will inform efforts to stimulate ADCC activity and improve its potency in vaccinees.
Identification of a Novel Antiviral Inhibitor of the Flavivirus Guanylyltransferase Enzyme
Authors: Stahla-Beek Hillary J. , April Daniel G. , Saeedi Bejan J. , Hannah Amanda M. , Keenan Susan M. , Geiss Brian J.
Published: June 2012

Arthropod-borne flavivirus infection causes serious morbidity and mortality worldwide, but there are currently no effective antiflaviviral chemotherapeutics available for human use. Therefore, it is critical that new therapeutics against virus-specific targets be developed. To identify new compounds that may be used as broadly active flavivirus therapeutics, we have performed a high-throughput screening of 235,456 commercially available compounds for small-molecule inhibitors of the dengue virus NS5 RNA capping enzyme. We identified a family of compounds, the 2-thioxothiazolidin-4-ones, that show potent biochemical inhibition of capping enzyme GTP binding and guanylyltransferase function. During the course of structure-activity relationship analysis, a molecule within this family, (E)-{3-[5-(4-
tert
-butylbenzylidene)-4-oxo-2-thioxo-1,3-thiazolidin-3-yl]propanoic acid} (BG-323), was found to possess significant antiviral activity in a dengue virus subgenomic replicon assay. Further testing of BG-323 demonstrated that this molecule is able to reduce the replication of infectious West Nile virus and yellow fever virus in cell culture with low toxicity. The results of this study describe the first inhibitor that targets the GTP-binding/guanylyltransferase activity of the flavivirus RNA capping enzyme.
Interactions between Proteins Encoded within the Human Cytomegalovirus
UL133-UL138
Locus
Authors: Petrucelli Alex , Umashankar Mahadevaiah , Zagallo Patricia , Rak Michael , Goodrum Felicia
Published: June 2012

We previously described a novel genetic locus within the UL
b
′ region of the human cytomegalovirus (HCMV) genome that, while dispensable for replication in fibroblasts, suppresses replication in hematopoietic progenitors and augments replication in endothelial cells. This locus, referred to as the
UL133-UL138
locus, encodes four proteins, pUL133, pUL135, pUL136, and pUL138. In this work, we have mapped the interactions among these proteins. An analysis of all pairwise interactions during transient expression revealed a robust interaction between pUL133 and pUL138. Potential interactions between pUL136 and both pUL133 and pUL138 were also revealed. In addition, each of the
UL133-UL138
locus proteins self-associated, suggesting a potential to form higher-order homomeric complexes. As both pUL133 and pUL138 function in promoting viral latency in CD34
+
hematopoietic progenitor cells (HPCs) infected
in vitro
, we further focused on this interaction. pUL133 and pUL138 are the predominant complex detected when all proteins are expressed together and require no other proteins in the locus for their association. During infection, the interaction between pUL133 and pUL138 or pUL136 can be detected. A recombinant virus that fails to express both pUL133 and pUL138 exhibited a latency phenotype similar to that of viruses that fail to express either pUL133 or pUL138, indicating that these proteins function cooperatively in latency and do not have independent functions that additively contribute to HCMV latency. These studies identify protein interactions among proteins encoded by the
UL133-UL138
locus and demonstrate an important interaction impacting the outcome of HCMV infection.
Identification of Novel T Cell Factor 4 (TCF-4) Binding Sites on the HIV Long Terminal Repeat Which Associate with TCF-4, β-Catenin, and SMAR1 To Repress HIV Transcription
Authors: Henderson Lisa J. , Narasipura Srinivas D. , Adarichev Vyacheslav , Kashanchi Fatah , Al-Harthi Lena
Published: June 2012

Molecular regulation of HIV transcription is a multifaceted process dictated in part by the abundance of cellular transcription factors that induce or repress HIV promoter activity. β-Catenin partners with members of the T cell factor (TCF)/LEF transcription factors to regulate gene expression. The interaction between β-catenin and TCF-4 is linked to inhibition of HIV replication in multiple cell types, including lymphocytes and astrocytes. Here, we evaluated the molecular mechanism by which β-catenin/TCF-4 repress HIV replication. We identified for the first time multiple TCF-4 binding sites at −336, −143, +66, and +186 relative to the transcription initiation site on the HIV long terminal repeat (LTR). Two of the sites (−143 and +66) were present in approximately 1/3 of 500 HIV-1 isolates examined. Although all four sites could bind to TCF-4, the strongest association occurred at −143. Deletion and/or mutation of −143, in conjunction with β-catenin or TCF-4 knockdown in cells stably expressing an LTR reporter construct, enhanced basal HIV promoter activity by 5-fold but had no effect on Tat-mediated transactivation of the HIV LTR. We also found that TCF-4, β-catenin, and the nuclear matrix binding protein SMAR1 tether at the −143-nucleotide (nt) site on the HIV LTR to inhibit HIV promoter activity. Collectively, these data indicate that TCF-4 and β-catenin at −143 associate with SMAR1, which likely pulls the HIV DNA segment into the nuclear matrix and away from transcriptional machinery, leading to repression of basal HIV LTR transcription. These studies point to novel avenues for regulation of HIV replication by manipulation of β-catenin signaling within cells.
Revisiting the Clinal Concept of Evolution and Dispersal for the Tick-Borne Flaviviruses by Using Phylogenetic and Biogeographic Analyses
Authors: Heinze D. M. , Gould E. A. , Forrester N. L.
Published: June 2012

Tick-borne flaviviruses (TBF) are widely dispersed across Africa, Europe, Asia, Oceania, and North America, and some present a significant threat to human health. Seminal studies on tick-borne encephalitis viruses (TBEV), based on partial envelope gene sequences, predicted a westward clinal pattern of evolution and dispersal across northern Eurasia, terminating in the British Isles. We tested this hypothesis using all available full-length open reading frame (ORF) TBF sequences. Phylogenetic analysis was consistent with current reports. However, linear and nonlinear regression analysis of genetic versus geographic distance combined with BEAST analysis identified two separate clines, suggesting that TBEV spread both east and west from a central point. In addition, BEAST analysis suggested that TBF emerged and dispersed more than 16,000 years ago, significantly earlier than previously predicted. Thus, climatic and ecological changes may have played a greater role in TBF dispersal than humans.
A multidimensional statistical model for wood data analysis, with density estimated from CT scanning data as an example
Authors: Manceur Ameur M. , Beaulieu Jean , Han Liwen , Dutilleul Pierre
Published: June 2012

The trunk of a tree can be seen as a spatiotemporal sampling domain from the statistical perspective, where space is represented by direction horizontally and height vertically, and time through annual growth rings. In this framework, wood properties such as density can be the object of data collection for given estimation and testing purposes. We present a multidimensional statistical model, the tensor normal distribution, in which the variation (variance) of and dependency (covariance) between wood property measurements made for different years at various locations in a tree trunk can be inferred. Its application requires a smaller number of replicates (trees) than the traditional vector normal distribution because variances and covariances for directions and growth rings, for example, must be the same at all heights, up to a multiplicative constant. This assumption on the variance–covariance structure is called “separability”, and we explain how to test it. An illustration with wood density estimates obtained from computed tomography scanning data for 11 white spruce ( Picea glauca (Moench) Voss) trees is presented. This example is completed by assessing differences in mean wood density according to location in the trunk, with analysis-of-variance F-tests adjusted for the estimated variances and covariances obtained by fitting the model.
Potential of decaying wood to restore root-available base cations in depleted forest soils
Authors: Shortle Walter C. , Smith Kevin T. , Jellison Jody , Schilling Jonathan S.
Published: June 2012

The depletion of root-available Ca in northern forest soils exposed to decades of increased acid deposition adversely affects forest health and productivity. Laboratory studies indicated the potential of wood-decay fungi to restore lost Ca. This study presents changes in concentration of Ca, Mg, and K in sapwood of red spruce ( Picea rubens Sarg.), red maple ( Acer rubrum L.), eastern hemlock ( Tsuga canadensis (L.) Carrière), and paper birch ( Betula papyrifera Marshall) during the decay process at two experimental forests for 12 years and to compare concentrations of exchangeable Ca, Mg, and Al in decayed wood residues at 10 and 12 years with those in the forest floor. Significant loss of mass indicated by decreasing wood density occurred after 2–8 years in conifers and after only 2 years in hardwoods. A significant gain in wood K was observed at 2 years followed by a significant loss at 8 years. A negligible gain in Ca concentration occurred at 2 years and a substantial gain at 8 years. Observed changes in Mg concentration were variable. No significant difference in exchangeable Ca concentration was observed between decayed wood residue of spruce and maple and the forest floor. However, decayed wood residue had a much lower Al concentration and molar Al/Ca ratio, a condition characteristic of sites with high root-available Ca.
Response of different white fir geographic provenances to Trichosporium symbioticum inoculation in California
Authors: Otrosina William J. , Zarnoch Stanley J.
Published: June 2012

We inoculated the fir engraver ( Scolytus ventralis LeConte) associated fungus Trichosporium symbioticum Wright onto 56 white fir ( Abies concolor (Gordon & Glend.) Lindl. ex Hildebr.) trees planted in a common garden study near Camino, California, that represented five geographic provenances of this species. The objective was to determine if there is a differential lesion length response of white fir provenances with respect to provenance. We found a significant (P < 0.019) difference between the provenances from Arizona and those of eastern Nevada origins 28 days after inoculation. There was a significant interaction between the two T. symbioticum isolates and season of inoculation. Fall inoculations tended to have smaller lesions than those in the spring but this varied by isolate in that the one from eastern Nevada tended to produce longer lesions in the spring (P = 0.0001) whereas the isolate from the Camino plantation did not differ between spring and fall (P = 1.000). There is evidence for genetic variability relative to white fir provenance lesion length in response to T. symbioticum inoculation, and in future studies, isolate variability should also be taken into account.
Modelling number, vertical distribution, and size of live branches on coniferous tree species in British Columbia
Authors: Nemec Amanda F. Linnell , Parish Roberta , Goudie James W.
Published: June 2012

A compound, nonhomogeneous Poisson process was used to model the number, vertical distribution, and size of branches on four coniferous tree species: 134 western hemlock ( Tsuga heterophylla (Raf.) Sarg.) on six sites, 45 amabilis fir ( Abies amabilis Douglas ex J. Forbes) (three sites), 60 lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Watson) (six sites), and 60 white spruce ( Picea glauca (Moench) Voss) trees (five sites) and two varieties: 66 coastal Douglas-fir ( Pseudotsuga menziesii var. menziesii (Mirb.) Franco) (five sites) and 50 interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Mayr) Franco) (four sites). Branches of these species are typically more or less clustered and have a characteristic, nonuniform vertical distribution along annual shoots. Total number and relative positions of clusters varied with shoot age. Clustering patterns in three of four species and two varieties appeared to scale proportionally with shoot length. However, in lodgepole pine, which has fewer clusters per metre and more branches per cluster, the vertical distribution of clusters along shoots ≤5 years old was consistent with a gamma-Poisson model but converged to a nonhomogeneous Poisson process model in shoots >5 years old. Separate mixed-effect regression models were developed for each species relating length and diameter of live branches to tree (crown), shoot, and branch (cluster) predictor variables.
Using blends of cerambycid beetle pheromones and host plant volatiles to simultaneously attract a diversity of cerambycid species
Authors: Hanks Lawrence M. , Millar Jocelyn G. , Mongold-Diers Judith A. , Wong Joseph C.H. , Meier Linnea R. , Reagel Peter F. , Mitchell Robert F.
Published: June 2012

We evaluated the attraction of native species of cerambycid beetles to blends of cerambycid pheromones and the host plant volatiles ethanol and α-pinene to determine whether such blends could be effective lures for detecting and monitoring multiple species. The complete six-component blend of pheromones included racemic 3-hydroxy-2-hexanone, 2,3-hexanediol isomers, (E)-6,10-dimethyl-5,9-undecadien-2-ol and the corresponding acetate, 2-(undecyloxy)-ethanol, and racemic 2-methyl-1-butanol. Bioassays in east-central Illinois captured 3070 cerambycid beetles of 10 species, including four species in the subfamily Cerambycinae ( Neoclytus acuminatus (Fabricius, 1775), Neoclytus mucronatus (Fabricius, 1775), Phymatodes lengi Joutel, 1911, and Xylotrechus colonus (Fabricius, 1775)) and six species in the subfamily Laminiae ( Aegomorphus modestus (Gyllenhal in Schoenherr, 1817), Astyleiopus variegatus (Haldeman, 1847), Astylidius parvus (LeConte, 1873), Graphisurus fasciatus (DeGeer, 1775), Lepturges angulatus (LeConte, 1852), and Monochamus carolinensis (Olivier, 1792)). Beetles were attracted to their pheromone components within the blend, with inhibition only evident in one species. Host plant volatiles synergized attraction for some species, and synergism usually was attributed to ethanol, with α-pinene enhancing attraction only for the pine specialist M. carolinensis. The optimal strategy for targeting a broad range of cerambycid species would be to bait traps with a blend of several pheromones plus ethanol and α-pinene because synergism by these plant volatiles is critical for some species, whereas strong inhibition is uncommon.