bluuebunny/crossref_metadata_2025 huggingface dataset:
17-β Estradiol Promotion of Herpes Simplex Virus Type 1 Reactivation Is Estrogen Receptor Dependent
Authors: Vicetti Miguel Rodolfo D. , Sheridan Brian S. , Harvey Stephen A. K. , Schreiner Robert S. , Hendricks Robert L. , Cherpes Thomas L.
Published: October 2009

Correlations between estrogen and herpes simplex virus (HSV) reactivation from latency have been suggested by numerous clinical reports, but causal associations are not well delineated. In a murine HSV-1 corneal infection model, we establish 17-β estradiol (17-βE) treatment of latently infected ovariectomized mice induces viral reactivation, as demonstrated by increased viral load and increased immediate-early viral gene expression in the latently infected trigeminal ganglia (TG). Interestingly, the increased HSV reactivation occurred in the absence of inhibition of viral specific CD8+T-cell effector function. 17-βE administration increased HSV reactivation in CD45+cell-depleted TG explant cultures, providing further support that leukocyte-independent effects on latently infected neurons were responsible for the increased reactivation. The drug-induced increases in HSV copy number were not recapitulated upon in vivo treatment of latently infected estrogen receptor alpha-deficient mice, evidence that HSV reactivation promoted by 17-βE was estrogen receptor dependent. These findings provide additional framework for the emerging conceptualization of HSV latency as a dynamic process maintained by complex interactions among multiple cooperative and competing host, viral, and environmental forces. Additional research is needed to confirm whether pregnancy or hormonal contraceptives containing 17-βE also promote HSV reactivation from latency in an estrogen receptor-dependent manner.
Interaction between Ebola Virus Glycoprotein and Host Toll-Like Receptor 4 Leads to Induction of Proinflammatory Cytokines and SOCS1
Authors: Okumura Atsushi , Pitha Paula M. , Yoshimura Akihiko , Harty Ronald N.
Published: October 2009

Ebola virus initially targets monocytes and macrophages, which can lead to the release of proinflammatory cytokines and chemokines. These inflammatory cytokines are thought to contribute to the development of circulatory shock seen in fatal Ebola virus infections. Here we report that host Toll-like receptor 4 (TLR4) is a sensor for Ebola virus glycoprotein (GP) on virus-like particles (VLPs) and that resultant TLR4 signaling pathways lead to the production of proinflammatory cytokines and suppressor of cytokine signaling 1 (SOCS1) in a human monocytic cell line and in HEK293-TLR4/MD2 cells stably expressing the TLR4/MD2 complex. Ebola virus GP was found to interact with TLR4 by immunoprecipitation/Western blot analyses, and Ebola virus GP on VLPs was able to stimulate expression of NF-κB in a TLR4-dependent manner. Interestingly, we found that budding of Ebola virus VLPs was more pronounced in TLR4-stimulated cells than in unstimulated control cells. In sum, these findings identify the host innate immune protein TLR4 as a sensor for Ebola virus GP which may play an important role in the immunopathogenesis of Ebola virus infection.
Abrogation of the Brd4-Positive Transcription Elongation Factor b Complex by Papillomavirus E2 Protein Contributes to Viral Oncogene Repression
Authors: Yan Junpeng , Li Qing , Lievens Sam , Tavernier Jan , You Jianxin
Published: October 2009

The cellular bromodomain protein Brd4 is a major interacting partner of the papillomavirus (PV) E2 protein. Interaction of E2 with Brd4 contributes to viral episome maintenance. The E2-Brd4 interaction also plays an important role in repressing viral oncogene expression from the integrated viral genome in human PV (HPV)-positive cancer cells. However, the underlying mechanism is not clearly understood. In host cells, Brd4 recruits positive transcription elongation factor b (P-TEFb) to stimulate RNA polymerase II phosphorylation during cellular and viral gene expression. P-TEFb associates with the C terminus of Brd4, which largely overlaps with the E2 binding site on Brd4. In this study, we demonstrate that E2 binding to Brd4 inhibits the interaction of endogenous Brd4 and P-TEFb. P-TEFb is essential for viral oncogene E6/E7 transcription in both HeLa and CaSki cells that contain integrated HPV genomes. E2 binding to Brd4 abrogates the recruitment of P-TEFb to the integrated viral chromatin template, leading to inactivation of P-TEFb and repression of the viral oncogene E6/E7. Furthermore, dissociation of the Brd4-P-TEFb complex from the integrated viral chromatin template using a Brd4 bromodomain dominant-negative inhibitor also hampers HPV E6/E7 oncogene expression. Our data support that Brd4 recruitment of P-TEFb to the viral chromatin template is essential for viral oncogene expression. Abrogation of the interaction between P-TEFb and Brd4 thus provides a mechanism for E2-mediated repression of the viral oncogenes from the integrated viral genomes in cancer cells.
Both RIG-I and MDA5 RNA Helicases Contribute to the Induction of Alpha/Beta Interferon in Measles Virus-Infected Human Cells
Authors: Ikegame Satoshi , Takeda Makoto , Ohno Shinji , Nakatsu Yuichiro , Nakanishi Yoichi , Yanagi Yusuke
Published: October 2009

Measles virus (MV), a member of the family
Paramyxoviridae
, is a nonsegmented negative-strand RNA virus. The RNA helicases retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) are differentially involved in the detection of cytoplasmic viral RNAs and induction of alpha/beta interferon (IFN-α/β). RIG-I is generally believed to play a major role in the recognition of paramyxoviruses, whereas many viruses of this family produce V proteins that can inhibit MDA5. To determine the individual roles of MDA5 and RIG-I in IFN induction after MV infection, small interfering RNA-mediated knockdown of MDA5 or RIG-I was performed in the human epithelial cell line H358, which is susceptible to wild-type MV isolates. The production of IFN-β mRNA in response to MV infection was greatly reduced in RIG-I knockdown clones compared to that in H358 cells, confirming the importance of RIG-I in the detection of MV. The IFN-β mRNA levels were also moderately reduced in MDA5 knockdown clones, even though these clones retained fully functional RIG-I. A V protein-deficient recombinant MV (MVΔV) induced higher amounts of IFN-β mRNA at the early stage of infection in H358 cells compared to the parental virus. The reductions in the IFN-β mRNA levels in RIG-I knockdown clones were less pronounced after infection with MVΔV than after infection with the parental virus. Taken together, the present results indicate that RIG-I and MDA5 both contribute to the recognition of MV and that the V protein promotes MV growth at least partly by inhibiting the MDA5-mediated IFN responses.
Targeting the Proteolytic Processing of the Viral Glycoprotein Precursor Is a Promising Novel Antiviral Strategy against Arenaviruses
Authors: Rojek Jillian M. , Pasqual Giulia , Sanchez Ana B. , Nguyen Ngoc-Thao , de la Torre Juan-Carlos , Kunz Stefan
Published: October 2009

A crucial step in the arenavirus life cycle is the biosynthesis of the viral envelope glycoprotein (GP) responsible for virus attachment and entry. Processing of the GP precursor (GPC) by the cellular proprotein convertase site 1 protease (S1P), also known as subtilisin-kexin-isozyme 1 (SKI-1), is crucial for cell-to-cell propagation of infection and production of infectious virus. Here, we sought to evaluate arenavirus GPC processing by S1P as a target for antiviral therapy using a recently developed peptide-based S1P inhibitor, decanoyl (dec)-RRLL-chloromethylketone (CMK), and the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV). To control for off-target effects of dec-RRLL-CMK, we employed arenavirus reverse genetics to introduce a furin recognition site into the GPC of LCMV. The rescued mutant virus grew to normal titers, and the processing of its GPC critically depended on cellular furin, but not S1P. Treatment with the S1P inhibitor dec-RRLL-CMK resulted in specific blocking of viral spread and virus production of LCMV. Combination of the protease inhibitor with ribavirin, currently used clinically for treatment of human arenavirus infections, resulted in additive drug effects. In cells deficient in S1P, the furin-dependent LCMV variant established persistent infection, whereas wild-type LCMV underwent extinction without the emergence of S1P-independent escape variants. Together, the potent antiviral activity of an inhibitor of S1P-dependent GPC cleavage, the additive antiviral effect with ribavirin, and the low probability of emergence of S1P-independent viral escape variants make S1P-mediated GPC processing by peptide-derived inhibitors a promising strategy for the development of novel antiarenaviral drugs.
Human Cytomegalovirus Induces the Interferon Response via the DNA Sensor ZBP1
Authors: DeFilippis Victor R. , Alvarado David , Sali Tina , Rothenburg Stefan , Früh Klaus
Published: October 2009

Human cytomegalovirus (HCMV) is a member of the betaherpesvirus family that, unlike other herpesviruses, triggers a strong innate immune response in infected cells that includes transcription of the beta interferon gene via activation of interferon regulatory factor 3 (IRF3). IRF3 activation requires signaling from pattern recognition receptors that is initiated by their interaction with specific pathogen-associated molecules. However, while IRF3-activating pathways are increasingly well characterized, the cellular molecules involved in HCMV-mediated IRF3-dependent beta interferon transcription are virtually unknown. We undertook a systematic examination of new and established IRF3-terminal pathway components to identify those that are essential to HCMV-triggered IRF3 activation. We show here that IRF3 activation induced by HCMV infection involves the newly identified protein STING but, in contrast to infections with other herpesviruses, occurs independently of the adaptor molecule IPS-1. We also show that the protein DDX3 contributes to HCMV-triggered expression of beta interferon. Moreover, we identify Z-DNA binding protein 1 (ZBP1) as being essential for IRF3 activation and interferon beta expression triggered by HCMV, as well as being sufficient to enhance HCMV-stimulated beta interferon transcription and secretion. ZBP1 transcription was also found to be induced following exposure to HCMV in a JAK/STAT-dependent manner, thus perhaps also contributing to a positive feedback signal. Finally, we show that constitutive overexpression of ZBP1 inhibits HCMV replication. ZBP1 was recently identified as a cytosolic pattern recognition receptor of double-stranded DNA, and thus, we propose a model for HCMV-mediated IRF3 activation that involves HCMV-associated DNA as the principal innate immune-activating pathogen-associated molecular pattern.
Murine Hepatitis Virus Nonstructural Protein 4 Regulates Virus-Induced Membrane Modifications and Replication Complex Function
Authors: Gadlage Mark J. , Sparks Jennifer S. , Beachboard Dia C. , Cox Reagan G. , Doyle Joshua D. , Stobart Christopher C. , Denison Mark R.
Published: October 2009

Positive-strand RNA viruses induce modifications of cytoplasmic membranes to form replication complexes. For coronaviruses, replicase nonstructural protein 4 (nsp4) has been proposed to function in the formation and organization of replication complexes. Murine hepatitis virus (MHV) nsp4 is glycosylated at residues Asn176 (N176) and N237 during plasmid expression of nsp4 in cells. To test if MHV nsp4 residues N176 and N237 are glycosylated during virus replication and to determine the effects of N176 and N237 on nsp4 function and MHV replication, alanine substitutions of nsp4 N176, N237, or both were engineered into the MHV-A59 genome. The N176A, N237A, and N176A/N237A mutant viruses were viable, and N176 and N237 were glycosylated during infection of wild-type (wt) and mutant viruses. The nsp4 glycosylation mutants exhibited impaired virus growth and RNA synthesis, with the N237A and N176A/N237A mutant viruses demonstrating more profound defects in virus growth and RNA synthesis. Electron microscopic analysis of ultrastructure from infected cells demonstrated that the nsp4 mutants had aberrant morphology of virus-induced double-membrane vesicles (DMVs) compared to those infected with wt virus. The degree of altered DMV morphology directly correlated with the extent of impairment in viral RNA synthesis and virus growth of the nsp4 mutant viruses. The results indicate that nsp4 plays a critical role in the organization and stability of DMVs. The results also support the conclusion that the structure of DMVs is essential for efficient RNA synthesis and optimal replication of coronaviruses.
Functional Analysis of a Cellular MicroRNA in Insect Host-Ascovirus Interaction
Authors: Hussain Mazhar , Asgari Sassan
Published: October 2009

MicroRNAs (miRNAs) have emerged as key regulators in many biological processes, from development to defense, at almost all organismal levels. Recently, their role has been highlighted in pathogen-host interactions. Emerging evidence from a variety of virus-host systems indicates that cellular as well as virally encoded miRNAs influence viral replication. Here, we report changes in expression levels of host miRNAs upon ascovirus infection in an insect cell line and investigated the role of a host miRNA, Hz-miR24, in the host-virus system. We found that Hz-miR24 is differentially expressed following virus infection, with an increase in its expression levels late in infection. Experimental evidence demonstrated that Hz-miR24 downregulates ascoviral DNA-dependent RNA polymerase and its β subunit transcript levels late in infection. The specific miRNA-target interactions were investigated and confirmed using the ectopic expression of Hz-miR24 and a green fluorescent protein-based reporter system. Further, the expression of the target gene was substantially enhanced in cells transfected with a synthesized inhibitor of Hz-miR24. These findings suggest that ascoviruses manipulate host miRNAs that in turn regulate the expression of their genes at specific time points after infection. To our knowledge, this is the first cellular miRNA reported to interact with an insect virus.
A Forward Genetic Strategy Reveals Destabilizing Mutations in the Ebolavirus Glycoprotein That Alter Its Protease Dependence during Cell Entry
Authors: Wong Anthony C. , Sandesara Rohini G. , Mulherkar Nirupama , Whelan Sean P. , Chandran Kartik
Published: October 2009

Ebolavirus (EBOV) entry into cells requires proteolytic disassembly of the viral glycoprotein, GP. This proteolytic processing, unusually extensive for an enveloped virus entry protein, is mediated by cysteine cathepsins, a family of endosomal/lysosomal proteases. Previous work has shown that cleavage of GP by cathepsin B (CatB) is specifically required to generate a critical entry intermediate. The functions of this intermediate are not well understood. We used a forward genetic strategy to investigate this CatB-dependent step. Specifically, we generated a replication-competent recombinant vesicular stomatitis virus bearing EBOV GP as its sole entry glycoprotein and used it to select viral mutants resistant to a CatB inhibitor. We obtained mutations at six amino acid positions in GP that independently confer complete resistance. All of the mutations reside at or near the GP1-GP2 intersubunit interface in the membrane-proximal base of the prefusion GP trimer. This region forms a part of the “clamp” that holds the fusion subunit GP2 in its metastable prefusion conformation. Biochemical studies suggest that most of the mutations confer CatB independence not by altering specific cleavage sites in GP but rather by inducing conformational rearrangements in the prefusion GP trimer that dramatically enhance its susceptibility to proteolysis. The remaining mutants did not show the preceding behavior, indicating the existence of multiple mechanisms for acquiring CatB independence during entry. Altogether, our findings suggest that CatB cleavage is required to facilitate the triggering of viral membrane fusion by destabilizing the prefusion conformation of EBOV GP.
African Swine Fever Virus Polyprotein pp62 Is Essential for Viral Core Development
Authors: Suárez Cristina , Salas María L. , Rodríguez Javier M.
Published: October 2009

One of the most characteristic features of African swine fever virus gene expression is its use of two polyproteins, pp220 and pp62, to produce several structural proteins that account for approximately 32% of the total protein virion mass. Equimolecular amounts of these proteins are the major components of the core shell, a thick protein layer that lies beneath the inner envelope, surrounding the viral nucleoid. Polyprotein pp220, which is located immediately underneath the internal envelope, is essential for the encapsidation of the core of the viral particle. In its absence, the infection produces essentially coreless particles. In this study we analyzed, by means of an IPTG (isopropyl-β-
d
-thiogalactopyranoside)-inducible virus, the role of polyprotein pp62 in virus assembly. Polyprotein pp62 is indispensable for viral replication. The repression of polyprotein pp62 expression does not alter late gene expression or the proteolytic processing of the polyprotein pp220. However, it has a profound impact on the subcellular localization of polyprotein pp220. Electron microscopy studies revealed that polyprotein pp62 is necessary for the correct assembly and maturation of the core of the viral particle. Its repression leads to the appearance of a significant fraction of empty particles, to an increase in the number of immature-like particles, and to the accumulation of defective particles. Immunoelectron microscopy analysis showed a clear correlation between the amount of polyprotein pp62, the quantity of polyprotein pp220, and the state of development of the core, suggesting that the complete absence of polyprotein pp62 during morphogenesis would produce a homogenous population of empty particles.
Different Tempo and Anatomic Location of Dual-Tropic and X4 Virus Emergence in a Model of R5 Simian-Human Immunodeficiency Virus Infection
Authors: Ren Wuze , Tasca Silvana , Zhuang Ke , Gettie Agegnehu , Blanchard James , Cheng-Mayer Cecilia
Published: October 2009

We previously reported coreceptor switch in rhesus macaques inoculated intravenously with R5 simian-human immunodeficiency virus SF162P3N (SHIV
SF162P3N
). Whether R5-to-X4 virus evolution occurs in mucosally infected animals and in which anatomic site the switch occurs, however, were not addressed. We herein report a change in coreceptor preference in macaques infected intrarectally with SHIV
SF162P3N
. The switch occurred in infected animals with high levels of virus replication and undetectable antiviral antibody response and required sequence changes in the V3 loop of the gp120 envelope protein. X4 virus emergence was associated with an accelerated drop in peripheral CD4
+
T-cell count but followed rather than preceded the onset of CD4
+
T-cell loss. The conditions, genotypic requirements, and patterns of coreceptor switch in intrarectally infected animals were thus remarkably consistent with those found in macaques infected intravenously. They also overlapped with those reported for humans, suggestive of a common mechanism for coreceptor switch in the two hosts. Furthermore, two independent R5-to-X4 evolutionary pathways were identified in one infected animal, giving rise to dual-tropic and X4 viruses which differed in switch kinetics and tissue localization. The dual-tropic switch event predominated early, and the virus established infection in multiple tissues sites. In contrast, the switch to X4 virus occurred later, initiating and expanding mainly in peripheral lymph nodes. These findings help define R5 SHIV
SF162P3N
infection of rhesus macaques as a model to study the mechanistic basis, dynamics, and sites of HIV-1 coreceptor switch.
Mechanisms of Protein Kinase PKR-Mediated Amplification of Beta Interferon Induction by C Protein-Deficient Measles Virus
Authors: McAllister Christopher S. , Toth Ann M. , Zhang Ping , Devaux Patricia , Cattaneo Roberto , Samuel Charles E.
Published: October 2009

The measles virus P gene products V and C antagonize the host interferon (IFN) response, blocking both IFN signaling and production. Using Moraten vaccine strain-derived measles virus and isogenic mutants deficient for either V or C protein production (V
ko
and C
ko
, respectively), we observed that the C
ko
virus was a potent inducer of IFN-β, while induction by V
ko
virus was an order of magnitude lower than that by the C
ko
virus. The parental recombinant Moraten virus did not significantly induce IFN-β. The enhanced IFN-inducing capacity of the C
ko
virus correlated with an enhanced activation of IFN regulatory factor 3 (IRF-3), NF-κB, and ATF-2 in C
ko
-infected compared to V
ko
or parental virus-infected cells. Furthermore, protein kinase PKR and mitochondrial adapter IPS-1 were required for maximal C
ko
-mediated IFN-β induction, which correlated with the PKR-mediated enhancement of mitogen-activated protein kinase and NF-κB activation. Our results reveal multiple consequences of C protein expression and document an important function for PKR as an enhancer of IFN-β induction during measles virus infection.
Women's rugby league injury claims and costs in New Zealand
Authors: King D A , Hume P A , Milburn P , Gianotti S
Published: October 2009

Aim

There is scarce information on rugby league injuries in female players. This paper provides an overview of the epidemiology of women's rugby league injuries requiring medical treatment and associated costs in New Zealand.

Method

New Zealand Accident Compensation Corporation injury data for the period 1999–2007 were searched for rugby league injury cases occurring in females. Data were analysed by demographics, body region, nature/severity of injury, and medical procedure and costs.

Results

There were 320 moderate to serious injury claims recorded for females participating in rugby league activities over the study period. There was a mean (SD) of 37.9 (9.5) injury claims per year. The mean cost per year for the study period was $196 514 ($99 133) (£76 066 (£38 374)) with half of the injury claims occurring in New Zealand Maori. Concussion/brain injuries accounted for 3.8% of total female moderate to serious injury claims but accounted for 5.4% of female injury costs ($84 399 (£32 688)) with the highest mean cost per claim ($7033 (£2724)). The lower limb accounted for 65% of the total female injury claims and 58.7% of total injury costs ($922 296 (£356 968)). The mean cost per claim was higher for the lower limb ($4434 (£1714)) than the upper ($3331 (£1288)) limb. Clerks recorded 16.3% of the total injury claims, 20.3% of total injury costs ($319 474 (£123 211)) and had the highest mean cost per claim ($6144 (£2370)). The 25–29 age group recorded 31.9% of injury claims and 33.8% of injury costs. The 35–39 age group recorded the highest mean cost per claim ($6200 (£2392)) but only 10.9% of total claims and 13.8% of total costs.

Discussion

When compared with other studies in rugby league injuries, it appears that females incur substantially fewer injuries (5.7%) than males (94.3%). Although no participation data by sex are available, it is likely that participation percentages are reflected in the injury percentages. The high frequency (65%) and cost proportion (58.7%) for lower limb injuries was higher in females than in male rugby league players (previously reported as 42.4% of the injury claims and 31.5% of the total injury claim costs for the lower limb).

Conclusions

Injury prevention programmes for women's rugby league should focus on the 25–29 age group and address ways to prevent concussion and lower limb injuries.
Physical fitness and indices of lifestyle-related diseases before and after interval walking training in middle-aged and older males and females
Authors: Morikawa M , Okazaki K , Masuki S , Kamijo Y , Yamazaki T , Gen-no H , Nose H
Published: October 2009

Hypothesis

Whether increasing peak aerobic capacity for walking (V̇2peak) by interval walking training (IWT) is closely linked with decreasing the indices of lifestyle-related diseases (LSDs) in middle-aged and older people were examined.

Methods

For 4 months from April to September 2005 or 2006, 246 males and 580 females (∼65 years) performed IWT consisting of ≥5 sets of fast walking at ≥70% V̇2peakfor 3 min followed by slow walking at ≤40% V̇2peakfor 3 min ≥4 days/week. Before and after IWT, we measured V̇2peak, body mass index (BMI), %body fat, arterial blood pressure, thigh muscle strength and blood parameters. We analysed 198 males and 468 females who had undergone all the measurements both before and after IWT. To examine the hypothesis, we divided the subjects equally into three groups according to their pretraining V̇2peak: low, middle and high groups for each sex.

Results

Before training, it was found that thigh muscle strength and blood high-density lipoprotein cholesterol concentration were lower, whereas body weight, BMI, %body fat, arterial blood pressure and blood glucose were higher in the low group than the high group (all, p<0.05). After training, although V̇2peakand thigh muscle strength increased and body weight, BMI, %body fat, blood pressure and blood glucose concentration decreased in all groups (all, p<0.05), the changes were greatest in the low group for both sexes.

Conclusion

V̇2peakat baseline and changes in response to training were closely linked with indices of LSDs.
Changes in the forms of invertase during the development of wheat leaves growing under cold-hardening and non-hardening conditions
Authors: Roberts D. W. A.
Published: October 2009

The proportion of peak I (molecular weight > 107) to peak II (molecular weight ca. 105) invertase increases in the leaves of common wheat, Triticum aestivum L. emend. Thell ssp. vulgare, as they age. Elongating leaf tissues produced at 21 °C contain much higher levels of peak I plus peak II invertase than do mature leaves. Most of this invertase is peak II material. In cold-hardened plants, old leaf tissues contain much more peak I plus peak II invertase than do young or elongating leaves. Such old leaves contain mostly peak I invertase.The ratio of peak I to peak II invertase in the leaves or roots from cold-hardened plants is higher than that from comparable tissues of non-hardened plants.Earlier data showed that the ratios of the quantities of peak I to peak II invertase are highly correlated with cold hardiness when a group of common wheats grown under the same hardening conditions are compared but not when a single variety is grown under different hardening conditions. The present data show that the ratio of peak I to peak II invertase changes as the tissues age. Consequently, comparing the ratios of peak I with peak II invertase in plants consisting of tissues that are not of comparable ages will confound the effects of tissue age and tissue cold hardiness. Good correlations between cold hardiness and the ratio of peak I to peak II invertase cannot be expected and were not found in earlier work under such conditions.
Taxonomic affinities and criteria for identification of the common ectendomycorrhizal symbiont of pines
Authors: Danielson R. M.
Published: October 2009

Evidence from cultured and soil-borne mycelium clearly indicates that the widespread mycorrhizal symbiont (or symbionts) known as the E-strain is an ascomycete anamorph. The evidence includes regular septation, the presence of Woronin bodies and injury- and age-induced septal plugs, sensitivity to benomyl, hyphal fusions, mode of hyphal repair, and morphology of the mycorrhizae. Isolates varied in the presence or absence of chlamydospores, pigmentation, growth rates, amount of aerial mycelium, and amount of hyphal ornamentation. It is uncertain whether one or more taxa is currently included in the E-strain concept.
Effects of long-term natural acidification on the algal communities of tundra ponds at the Smoking Hills, N.W.T., Canada
Authors: Sheath R. G. , Havas M. , Hellebust J. A. , Hutchinson T. C.
Published: October 2009

Epipelic and planktonic algal communities have been examined periodically for 3 years from four tundra ponds which have very low pH values (1.8–3.6) and high heavy metal concentrations due to long-term fumigation by sulphur dioxide and sulphuric acid aerosols from nearby lignite burns. These communities have been compared with those of control ponds which are situated further from the burns and have alkaline waters (pH 8) due to calcareous marl soils. The 90 species identified from the control ponds are members of nine classes of algae. In contrast, 14 species have been observed in the fumigated ponds which are representatives of four classes, the Chlorophyceae, Euglenophyceae, Bacillariophyceae, and Cryptophyceae. The plankton of the control ponds is typical of tundra ponds in that it is dominated by small flagellates, particularly the cryptomonad Chroomonas minuta. Diatoms such as Amphora, Navicula and Surirella species, are the major components of the epipelic periphyton of these ponds, accounting for 67 to 90% of the biomass. Most of the primary productivity and biomass of the algae in the acidified ponds is benthic (3.7 versus 0.17 mg C m−2 h−1 for epipelon and plankton, respectively). The dominant species in the fumigated ponds include Chlamydomonas acidophila, Euglena mutabilis, Nitzschia communis, Eunotia arcus, and Eunotia glacialis. Fine structural examination of Euglena and Nitzschia indicates that these species are healthy under conditions of pH 1.8 and high heavy metals. These results show that the flora of the fumigated ponds is atypical of tundra ponds but rather is similar to that of very acidic temperate waters such as those draining coal-mined areas or volcanic lakes.
Solute leakage from susceptible and tolerant cultivars of Phaseolus vulgaris following ozone exposure
Authors: McKersie B. D. , Hucl P. , Beversdorf W. D.
Published: October 2009

The leakage of total electrolytes, potassium, calcium, sugars, and amino acids from primary leaf discs of Phaseolus vulgaris L. cv. Seafarer (ozone susceptible) and cv. Goldcrop (ozone tolerant) was monitored following exposure to 40 parts per hundred million (pphm) ozone for 4 h. Significant differences in cultivar response were not detected until 24 h after exposure. At that time, leakage from cv. Seafarer leaves was 220% for total electrolytes, 230% for calcium, 260% for potassium and sugars, and 400% for amino acids relative to controls, whereas the leakage from cv. Goldcrop leaves remained at control levels. The water-soluble sugar and free amino acid content of a leaf homogenate also increased at the 24-h sampling time. These accumulations may result from a reduced rate of phloem translocation. Rates of leakage and leaf-solute contents returned to control levels by 48 and 72 h after exposure.Kinetic analysis of solute efflux from leaf discs sampled from both cultivars immediately after ozone exposure indicated that these leaves contained an increased quantity of solutes which could be rapidly leached within 0.5 h. However, the subsequent linear rate of leakage between 0.5 and 4 h did not increase except in leaf discs sampled from cv. Seafarer 24 h after exposure. The results are discussed in relation to the mechanism of ozone injury in cv. Seafarer and the basis of ozone tolerance in the cv. Goldcrop.
Cellular components of the midstylar transmitting tissue of Prunus avium
Authors: Uwate W. J. , Lin J. , Ryugo K. , Stallman V.
Published: October 2009

Proportions of cellular components in the midstylar transmitting tissue of Prunus avium L., sweet cherry, were determined using the point interception method on transmission electron micrographs. Changes were measured during the development of the style when comparing pistils collected 1 week before anthesis with unpollinated pistils at the anthesis stage. Transmitting tissue was also examined 20 h after cross- and self-pollination. The results illustrate complex patterns of cellular development including changes in vacuolation, cell wall – intercellular substances, and starch. Other cellular components were also quantified and are discussed. After pollination, further cell wall – intercellular substances increases occur but no differences were found between cross- and self-pollination.
ON TOPOLOGICAL CHARGED BRANEWORLD BLACK HOLES
Authors: SHEYKHI AHMAD , WANG BIN
Published: October 2009

We study a class of topological black hole solutions in RSII braneworld scenario in the presence of a localized Maxwell field on the brane. Such a black hole can carry two types of charge, one arising from the extra dimension, the tidal charge, and the other from a localized gauge field confined to the brane. We find that the localized charge on the brane modifies the bulk geometry and in particular the bulk Weyl tensor. The bulk geometry does not depend on different topologies of the horizons. We present the temperature and entropy expressions associated with the event horizon of the braneworld black hole and by using the first law of black hole thermodynamics we calculate the mass of the black hole.
THE AMPLITUDE OF THE DE BROGLIE GRAVITATIONAL WAVES
Authors: FEOLI ANTONIO
Published: October 2009

We calculate the amplitude of the de Broglie gravitational waves using the standard Einstein General Relativity. We find that these waves disappear in the limit ℏ→0 and when their source has a large mass and volume. From the experimental point of view, the knowledge of the amplitude allows to estimate the magnitude of the effect of the wave on a sphere of test particles. We propose also to measure a very special shift angle that does not change with time.
STRING PHENOMENOLOGY AT THE LHC
Authors: ANCHORDOQUI LUIS A. , GOLDBERG HAIM , LÜST DIETER , STIEBERGER STEPHAN , TAYLOR TOMASZ R.
Published: October 2009

We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale is in the TeV range and the theory is weakly coupled, we review possible signals of string physics at the Large Hadron Collider.
Angiotensin II enhances hyperpolarization-activated currents in rat aortic baroreceptor neurons: involvement of superoxide
Authors: Zhang Libin , Tu Huiyin , Li Yu-Long
Published: October 2009

As an endogenous physiologically active peptide, angiotensin (ANG) II plays an important role in the maintenance of blood pressure. In the arterial baroreceptor reflex (a pivotal regulator of blood pressure), aortic baroreceptor (AB) neurons located in the nodose ganglia (NG) are a primary afferent limb of the baroreflex. Hyperpolarization-activated currents ( Ih) in the AB neurons contribute to the excitability of the AB neurons. Therefore, the present study was to measure the modulating effect of ANG II on the Ih in the primary AB neurons isolated from rats. Data from immunofluorescent and Western blot analyses showed that protein of AT1 and AT2 receptors was expressed in the nodose neurons. In the whole cell patch-clamp recording, ANG II concentration dependently enhanced the Ih density in the AB neurons (100 nM ANG II-induced 53.8 ± 3.8% increase for A-type AB neurons and 30.4 ± 7.7% increase for C-type AB neurons at test pulse −140 mV, P < 0.05). ANG II also decreased membrane excitability in the AB neurons. AT1 receptor antagonist (1 μM losartan) but not AT2 receptor antagonist (1 μM PD-123,319) totally abolished the effect of ANG II on the Ih and neuronal excitability. In addition, NADPH oxidase inhibitor (100 μM apocynin) and superoxide scavenger (1 mM tempol) also significantly blunted the ANG II-induced increase of the Ih and decrease of the membrane excitability in the AB neurons. Furthermore, losartan, apocynin, or tempol significantly attenuated the superoxide overproduction in the NG tissues induced by ANG II. These results suggest that ANG II-NADPH oxidase-superoxide signaling can activate the Ih and subsequently decrease the membrane excitability of rat AB neurons.
Febrile-range temperature modifies cytokine gene expression in LPS-stimulated macrophages by differentially modifying NF-κB recruitment to cytokine gene promoters
Authors: Cooper Zachary A. , Ghosh Arundhati , Gupta Aditi , Maity Tapan , Benjamin Ivor J. , Vogel Stefanie N. , Hasday Jeffrey D. , Singh Ishwar S.
Published: October 2009

We previously showed that exposure to febrile-range temperatures (FRT, 39.5–40°C) reduces LPS-induced TNF-α expression, in part through the direct interaction of heat shock factor-1 (HSF1) with the TNF-α gene promoter. However, it is not known whether exposure to FRT also modifies more proximal LPS-induced signaling events. Using HSF1-null mice, we confirmed that HSF1 is required for FRT-induced repression of TNF-α in vitro by LPS-stimulated bone marrow-derived macrophages and in vivo in mice challenged intratracheally with LPS. Exposing LPS-stimulated RAW 264.7 mouse macrophages to FRT reduced TNF-α expression while increasing IL-1β expression despite the two genes sharing a common myeloid differentiation protein-88 (MyD88)-dependent pathway. Global activation of the three LPS-induced signaling intermediates that lead to cytokine gene expression, ERK and p38 MAPKs and NF-κB, was not affected by exposing RAW 264.7 cells to FRT as assessed by ERK and p38 phosphorylation and NF-κB in vitro DNA-binding activity and activation of a NF-κB-dependent synthetic promoter. However, chromatin immunoprecipitation (ChIP) analysis demonstrated that exposure to FRT reduced LPS-induced recruitment of NF-κB p65 to the TNF-α promoter while simultaneously increasing its recruitment to the IL-1β promoter. These data suggest that FRT exerts its effects on cytokine gene expression in a gene-specific manner through distal effects on promoter activation rather than proximal receptor activation and signal transduction.
Deregulation of apoptotic volume decrease and ionic movements in multidrug-resistant tumor cells: role of chloride channels
Authors: Poulsen K. A. , Andersen E. C. , Hansen C. F. , Klausen T. K. , Hougaard C. , Lambert I. H. , Hoffmann E. K.
Published: October 2009

Changes in cell volume and ion gradients across the plasma membrane play a pivotal role in the initiation of apoptosis. Here we explore the kinetics of apoptotic volume decrease (AVD) and ion content dynamics in wild-type (WT) and multidrug-resistant (MDR) Ehrlich ascites tumor cells (EATC). In WT EATC, induction of apoptosis with cisplatin (5 μM) leads to three distinctive AVD stages: an early AVD1 (4–12 h), associated with a 30% cell water loss; a transition stage AVDT (∼12 to 32 h), where cell volume is partly recovered; and a secondary AVD2 (past 32 h), where cell volume was further reduced. AVD1 and AVD2 were coupled to net loss of Cl−, K+, Na+, and amino acids (ninhydrin-positive substances), whereas during AVDT, Na+ and Cl− were accumulated. MDR EATC was resistant to cisplatin, showing increased viability and less caspase 3 activation. Compared with WT EATC, MDR EATC underwent a less pronounced AVD1, an augmented AVDT, and a delay in induction of AVD2. Changes in AVD were associated with inhibition of Cl− loss during AVD1, augmented NaCl uptake during AVDT, and a delay of Cl− loss during AVD2. Application of the anion channel inhibitor NS3728 inhibited AVD and completely abolished the differences in AVD, ionic movements, and caspase 3 activation between WT and MDR EATC. Finally, the maximal capacity of volume-regulated anion channel was found to be strongly repressed in MDR EATC. Together, these data suggest that impairment of AVD, primarily via modulation of NaCl movements, contribute to protection against apoptosis in MDR EATC.
Heterogeneous activity level of jaw-closing and -opening muscles and its association with arousal levels during sleep in the guinea pig
Authors: Kato Takafumi , Masuda Yuji , Kanayama Hayato , Nakamura Norimasa , Yoshida Atsushi , Morimoto Toshifumi
Published: October 2009

Exaggerated jaw motor activities during sleep are associated with muscle symptoms in the jaw-closing rather than the jaw-opening muscles. The intrinsic activity of antagonistic jaw muscles during sleep remains unknown. This study aims to assess the balance of muscle activity between masseter (MA) and digastric (DG) muscles during sleep in guinea pigs. Electroencephalogram (EEG), electroocculogram, and electromyograms (EMGs) of dorsal neck, MA, and DG muscles were recorded with video during sleep-wake cycles. These variables were quantified for each 10-s epoch. The magnitude of muscle activity during sleep in relation to mean EMG activity of total wakefulness was up to three times higher for MA muscle than for DG muscle for nonrapid eye movement (NREM) and rapid-eye-movement (REM) sleep. Although the activity level of the two jaw muscles fluctuated during sleep, the ratio of activity level for each epoch was not proportional. Epochs with a high activity level for each muscle were associated with a decrease in δEEG power and/or an increase in heart rate in NREM sleep. However, this association with heart rate and activity levels was not observed in REM sleep. These results suggest that in guinea pigs, the magnitude of muscle activity for antagonistic jaw muscles is heterogeneously modulated during sleep, characterized by a high activity level in the jaw-closing muscle. Fluctuations in the activity are influenced by transient arousal levels in NREM sleep but, in REM sleep, the distinct controls may contribute to the fluctuation. The above intrinsic characteristics could underlie the exaggeration of jaw motor activities during sleep (e.g., sleep bruxism).
Neonatal exendin-4 treatment reduces oxidative stress and prevents hepatic insulin resistance in intrauterine growth-retarded rats
Authors: Raab Elisabeth L. , Vuguin Patricia M. , Stoffers Doris A. , Simmons Rebecca A.
Published: October 2009

Intrauterine growth retardation (IUGR) has been linked to the development of Type 2 diabetes in adulthood. We have developed an IUGR model in the rat whereby the animals develop diabetes later in life. Previous studies demonstrate that administration of the long-acting glucagon-like-peptide-1 agonist, Exendin-4, during the neonatal period prevents the development of diabetes in IUGR rats. IUGR animals exhibit hepatic insulin resistance early in life (prior to the onset of hyperglycemia), characterized by blunted suppression of hepatic glucose production (HGP) in response to insulin. Basal HGP is also significantly higher in IUGR rats. We hypothesized that neonatal administration of Exendin-4 would prevent the development of hepatic insulin resistance. IUGR and control rats were given Exendin-4 on days 1–6 of life. Hyperinsulinemic-euglycemic clamp studies showed that Ex-4 significantly reduced basal HGP by 20% and normalized insulin suppression of HGP in IUGR rats. While Ex-4 decreased body weight and fat content in both Control and IUGR animals, these differences were only statistically significant in Controls. Exendin-4 prevented development of oxidative stress in liver and reversed insulin-signaling defects in vivo, thereby preventing the development of hepatic insulin resistance. Defects in glucose disposal and suppression of hepatic glucose production in response to insulin were reversed. Similar results were obtained in isolated Ex-4-treated neonatal hepatocytes. These results indicate that exposure to Exendin-4 in the newborn period reverses the adverse consequences of fetal programming and prevents the development of hepatic insulin resistance.
ERK5 activation enhances mesangial cell viability and collagen matrix accumulation in rat progressive glomerulonephritis
Authors: Urushihara Maki , Takamatsu Masanori , Shimizu Maki , Kondo Shuji , Kinoshita Yukiko , Suga Kenichi , Kitamura Akiko , Matsuura Sato , Yoshizumi Masanori , Tamaki Toshiaki , Kawachi Hiroshi , Kagami Shoji
Published: October 2009

The mitogen-activated protein kinase (MAPK) cascade plays an important role in the regulation of various cellular functions in glomerulonephritis (GN). Here, we investigated whether extracellular signal-regulated kinase 5 (ERK5), a member of the MAPK family, is involved in the pathogenesis of chronic mesangioproliferative GN, using a rat model induced by uninephrectomy and anti-Thy-1 antibody injection. Immunostaining of kidneys obtained at different time points revealed that phospho-ERK5 was weakly expressed in control glomeruli but dramatically increased in a typical mesangial pattern after 28 and 56 days of GN. A semiquantitative assessment indicated that glomerular phospho-ERK5 expression closely paralleled the accumulation of extracellular matrix (ECM), collagen type I, as well as glomerular expression of reactive oxygen species (ROS) and ANG II. On the other hand, phospho-ERK1/2 expression increased on day 7 during the phase of enhanced mesangial cell (MC) proliferation and decreased thereafter. H2O2and ANG II each induced ERK5 phosphorylation by cultured rat MCs. Costimulation with both H2O2and ANG II synergistically increased ERK5 phosphorylation in MCs. Cultured MCs transfected with ERK5-specific small interference RNA showed a significant decrease in H2O2or ANG II-induced cell viability and soluble collagen secretion compared with control cells. Treatment of GN rats with an ANG II type 1 receptor blocker resulted in significant decreases in phospho-ERK5 expression and collagen accumulation accompanied by remarkable histological improvement. Taken together, these results suggest that MC ERK5 phosphorylation by ANG II or H2O2enhances cell viability and ECM accumulation in an experimental model of chronic GN.
Involuntary breathing movements improve cerebral oxygenation during apnea struggle phase in elite divers
Authors: Dujic Zeljko , Uglesic Lovro , Breskovic Toni , Valic Zoran , Heusser Karsten , Marinovic Jasna , Ljubkovic Marko , Palada Ivan
Published: October 2009

We investigated whether the involuntary breathing movements (IBM) during the struggle phase of breath holding, together with peripheral vasoconstriction and progressive hypercapnia, have a positive effect in maintaining cerebral blood volume. The central hemodynamics, arterial oxygen saturation, brain regional oxyhemoglobin (bHbO2), deoxyhemoglobin, and total hemoglobin changes and IBM were monitored during maximal dry breath holds in eight elite divers. The frequency of IBM increased (by ∼100%), and their duration decreased (∼30%), toward the end of the struggle phase, whereas the amplitude was unchanged (compared with the beginning of the struggle phase). In all subjects, a consistent increase in brain regional deoxyhemoglobin and total hemoglobin was also found during struggle phase, whereas bHbO2 changed biphasically: it initially increased until the middle of the struggle phase, with the subsequent relative decline at the end of the breath hold. Mean arterial pressure was elevated during the struggle phase, although there was no further rise in the peripheral resistance, suggesting unchanged peripheral vasoconstriction and implying the beneficial influence of the IBM on the cardiac output recovery (primarily by restoration of the stroke volume). The IBM-induced short-lasting, sudden increases in mean arterial pressure were followed by similar oscillations in bHbO2. These results suggest that an increase in the cerebral blood volume observed during the struggle phase of dry apnea is most likely caused by the IBM at the time of the hypercapnia-induced cerebral vasodilatation and peripheral vasoconstriction.