bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Interferon in Homologous and Heterologous Rotavirus Infection in the Intestines and Extraintestinal Organs of Suckling Mice
Authors: Feng N. , Kim B. , Fenaux M. , Nguyen H. , Vo P. , Omary M. B. , Greenberg H. B.
Published: May 2008

Recent studies demonstrated that viremia and extraintestinal rotavirus infection are common in acutely infected humans and animals, while systemic diseases appear to be rare. Intraperitoneal infection of newborn mice with rhesus rotavirus (RRV) results in biliary atresia (BA), and this condition is influenced by the host interferon response. We studied orally inoculated 5-day-old suckling mice that were deficient in interferon (IFN) signaling to evaluate the role of interferon on the outcome of local and systemic infection after enteric inoculation. We found that systemic replication of RRV, but not murine rotavirus strain EC, was greatly enhanced in IFN-α/β and IFN-γ receptor double-knockout (KO) or STAT1 KO mice but not in mice deficient in B- or T-cell immunity. The enhanced replication of RRV was associated with a lethal hepatitis, pancreatitis, and BA, while no systemic disease was observed in strain EC-infected interferon-deficient mice. In IFN-α/β receptor KO mice the extraintestinal infection and systemic disease were only moderately increased, while RRV infection was not augmented and systemic disease was not present in IFN-γ receptor KO mice. The increase of systemic infection in IFN-deficient mice was also observed during simian strain SA11 infection but not following bovine NCDV, porcine OSU, or murine strain EW infection. Our data indicate that the requirements for the interferon system to inhibit intestinal and extraintestinal viral replication in suckling mice vary among different heterologous and homologous rotavirus strains, and this variation is associated with lethal systemic disease.
Repeated Passage of Wild-Type Woodchuck Hepatitis Virus in Lymphoid Cells Does Not Generate Cell Type-Specific Variants or Alter Virus Infectivity
Authors: Mulrooney-Cousins Patricia M. , Michalak Tomasz I.
Published: May 2008

Woodchuck hepatitis virus (WHV), which is closely related to human hepatitis B virus, infects the liver but also invariably establishes persistent infection in the lymphatic system. Although the dose of invading virus appears to be the main factor in determining whether WHV infection is restricted to the lymphatic system or also engages the liver, the nature of WHV lymphotropism remains unclear and a role for a specific lymphotropic variant was not excluded. The availability of woodchuck lymphocyte and hepatocyte cultures susceptible to WHV infection allows investigation of this issue in vitro. We hypothesized that repeated passage of wild-type WHV in lymphoid cells should lead to enrichment of a lymphotropic virus variant, if in fact such a variant exists. For this purpose, wild-type WHV with a homogeneous sequence was used as the inoculum, while lymphoid cells from a single healthy woodchuck donor and a normal woodchuck WCM-260 hepatocyte line served as infection targets. The serial passage of the wild-type virus repeated up to 13 times for both cell types did not lead to the emergence of cell type-specific WHV variants, as revealed by sequence analysis of the virus envelope and the core and X gene sequences. Moreover, the virus passaged in both cell types remained infectious for naive woodchucks, produced infection profiles that depended upon virus dose but not on virus cellular origin, and retained its initial DNA sequence. These results imply that WHV lymphotropism is a natural propensity of the wild-type virus and is not a consequence of infection with a viral variant.
In Vivo Emergence of Vicriviroc Resistance in a Human Immunodeficiency Virus Type 1 Subtype C-Infected Subject
Authors: Tsibris Athe M. N. , Sagar Manish , Gulick Roy M. , Su Zhaohui , Hughes Michael , Greaves Wayne , Subramanian Mani , Flexner Charles , Giguel Françoise , Leopold Kay E. , Coakley Eoin , Kuritzkes Daniel R.
Published: May 2008

Little is known about the in vivo development of resistance to human immunodeficiency virus type 1 (HIV-1) CCR5 antagonists. We studied 29 subjects with virologic failure from a phase IIb study of the CCR5 antagonist vicriviroc (VCV) and identified one individual with HIV-1 subtype C who developed VCV resistance. Studies with chimeric envelopes demonstrated that changes within the V3 loop were sufficient to confer VCV resistance. Resistant virus showed VCV-enhanced replication, cross-resistance to another CCR5 antagonist, TAK779, and increased sensitivity to aminooxypentane-RANTES and the CCR5 monoclonal antibody HGS004. Pretreatment V3 loop sequences reemerged following VCV discontinuation, implying that VCV resistance has associated fitness costs.
Improved Induction of Antibodies against Key Neutralizing Epitopes by Human Immunodeficiency Virus Type 1 gp120 DNA Prime-Protein Boost Vaccination Compared to gp120 Protein-Only Vaccination
Authors: Vaine Michael , Wang Shixia , Crooks Emma T. , Jiang Pengfei , Montefiori David C. , Binley James , Lu Shan
Published: May 2008

A major challenge in human immunodeficiency virus type 1 (HIV-1) vaccine development is to elicit potent and broadly neutralizing antibodies that are effective against primary viral isolates. Previously, we showed that DNA prime-protein boost vaccination using HIV-1 gp120 antigens was more effective in eliciting neutralizing antibodies against primary HIV-1 isolates than was a recombinant gp120 protein-only vaccination approach. In the current study, we analyzed the difference in antibody specificities in rabbit sera elicited by these two immunization regimens using peptide enzyme-linked immunosorbent assay and a competitive virus capture assay. Our results indicate that a DNA prime-protein boost regimen is more effective than a protein-alone vaccination approach in inducing antibodies that target two key neutralizing domains: the V3 loop and the CD4 binding site. In particular, positive antibodies targeting several peptides that overlap with the known CD4 binding area were detected only in DNA-primed sera. Different profiles of antibody specificities provide insight into the mechanisms behind the elicitation of better neutralizing antibodies with the DNA prime-protein boost approach, and our results support the use of this approach to further optimize Env formulations for HIV vaccine development.
Severe Acute Respiratory Syndrome Coronavirus Infection Causes Neuronal Death in the Absence of Encephalitis in Mice Transgenic for Human ACE2
Authors: Netland Jason , Meyerholz David K. , Moore Steven , Cassell Martin , Perlman Stanley
Published: May 2008

Infection of humans with the severe acute respiratory syndrome coronavirus (SARS-CoV) results in substantial morbidity and mortality, with death resulting primarily from respiratory failure. While the lungs are the major site of infection, the brain is also infected in some patients. Brain infection may result in long-term neurological sequelae, but little is known about the pathogenesis of SARS-CoV in this organ. We previously showed that the brain was a major target organ for infection in mice that are transgenic for the SARS-CoV receptor (human angiotensin-converting enzyme 2). Herein, we use these mice to show that virus enters the brain primarily via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain. This extensive neuronal infection is the main cause of death because intracranial inoculation with low doses of virus results in a uniformly lethal disease even though little infection is detected in the lungs. Death of the animal likely results from dysfunction and/or death of infected neurons, especially those located in cardiorespiratory centers in the medulla. Remarkably, the virus induces minimal cellular infiltration in the brain. Our results show that neurons are a highly susceptible target for SARS-CoV and that only the absence of the host cell receptor prevents severe murine brain disease.
Transmission of Human Immunodeficiency Virus Type 1 from a Patient Who Developed AIDS to an Elite Suppressor
Authors: Bailey Justin R. , O'Connell Karen , Yang Hung-Chih , Han Yefei , Xu Jie , Jilek Benjamin , Williams Thomas M. , Ray Stuart C. , Siliciano Robert F. , Blankson Joel N.
Published: May 2008

Elite suppressors (ES) are untreated human immunodeficiency virus type 1 (HIV-1)-infected patients who maintain viral loads of <50 copies/ml. The mechanisms involved in this control of viral replication remain unclear. Prior studies suggested that these patients, as well as long-term nonprogressors, are infected with defective HIV-1 variants. Other reports have shown that the HLA-B*27 and -B*57 alleles are overrepresented in these patients, suggesting that host factors play a role in the control of viral replication. In order to distinguish between these hypotheses, we studied differences in viral isolates and immune responses of an HIV-1 transmission pair. While both patients are HLA-B*57 positive, the transmitter progressed to AIDS, whereas the recipient, who is also HLA-B*27 positive, is an ES. Isolates from both patients were replication competent and contained the T242N escape mutation in Gag, which is known to decrease viral fitness. While the acquisition of compensatory mutations occurred in isolates from the progressor, a superior HIV-specific CD8
+
T-cell response in the ES appears to have prevented viral replication and thus the evolution toward a more fit variant. In addition, CD8
+
T cells in the ES have selected for a rare mutation in an immunodominant HLA-B*27-restricted Gag epitope, which also has a negative impact on fitness. The results strongly suggest that through direct and indirect mechanisms, CD8
+
T cells in some ES control HIV-1 isolates are capable of causing profound immunosuppression.
Investigation of Putative Multisubtype Hepatitis C Virus Infections In Vivo by Heteroduplex Mobility Analysis of Core/Envelope Subgenomes
Authors: Li Hui , Thomassen Lisa V. , Majid Ayaz , McMahon Brian J. , Bruden Dana , McArdle Susan , Bano Nazneen , Chung Minjun , Carithers Robert L. , Perkins James D. , Sullivan Daniel G. , Gretch David R.
Published: May 2008

The frequency that multiple different subtypes of hepatitis C virus (HCV) simultaneously infect a given individual is controversial. To address this question, heteroduplex mobility analysis (HMA) of portions of the HCV core and envelope 1 region was optimized for sensitive and specific detection of mixtures of HCV genomes of different genotype or subtype. Using the standard HCV genotyping approach of 5′-untranslated region (UTR) analysis, 28 of 374 (7.5%) chronic hepatitis C research subjects were classified as having either multiple-subtype HCV infections (
n
= 21) or switching HCV subtypes over time (
n
= 7), the latter pattern implying viral superinfection. Upon retesting of specimens by HMA, 25 of 28 multiple-subtype results could not be reproduced. All three patients with positive results were injection drug users with potential multiple HCV exposures. To address the hypothesis of tissue sequestration of multiple-subtype HCV infections, liver (
n
= 22), peripheral blood mononuclear cell (
n
= 13), perihepatic lymph node (
n
= 16), and serum (
n
= 19) specimens from 23 subjects with end-stage hepatitis C were collected and analyzed by the HMA technique. Whereas 5′-UTR results implicated mixed-subtype HCV infections in 2 subjects, HMA testing revealed no evidence of a second HCV subtype in any tissue compartment (0 of 70 compartments [0%]) or within any given subject (0 of 23 subjects [0%]). In summary, a large proportion of mixed-genotype and switching-genotype patterns generated by 5′-UTR analysis were not reproducible using the HMA approach, emphasizing the need for additional study.
Cross Talk between Expression of the Human T-Cell Leukemia Virus Type 1 Tax Transactivator and the Oncogenic bHLH Transcription Factor TAL1
Authors: Terme Jean-Michel , Wencker Melanie , Favre-Bonvin Arnaud , Bex Françoise , Gazzolo Louis , Duc Dodon Madeleine , Jalinot Pierre
Published: May 2008

The human T-cell leukemia virus type 1 (HTLV-1) Tax transactivator is known to induce or repress various cellular genes, several of them encoding transcription factors. As Tax is known to deregulate various basic bHLH factors, we looked more specifically at its effect on TAL1 (T-cell acute lymphoblastic leukemia 1), also known as SCL (stem cell leukemia). Indeed, TAL1 is deregulated in a high percentage of T-cell acute lymphoblastic leukemia cells, and its oncogenic properties are well-established. Here we show that Tax induces transcription of this proto-oncogene by stimulating the activity of the
TAL1
gene promoter 1b, through both the CREB and NF-κB pathways. It was also observed that TAL1 upregulates HTLV-1 promoter activity, in either the presence or the absence of Tax. The viral promoter is inhibited in
trans
by expression of the E2A protein E47, and TAL1 is able to abrogate this inhibition. These data show the existence of a positive feedback loop between Tax and TAL1 expression and support the notion that this proto-oncogene participates in generation of adult T-cell leukemia/lymphoma by increasing the amount of the Tax oncoprotein but also possibly by its own transforming activities.
Establishment of B-Cell Lines Latently Infected with Reactivation-Competent Murine Gammaherpesvirus 68 Provides Evidence for Viral Alteration of a DNA Damage-Signaling Cascade
Authors: Forrest J. Craig , Speck Samuel H.
Published: May 2008

Gammaherpesvirus 68 (γHV68, or MHV68) is a naturally occurring rodent pathogen that replicates to high titer in cell culture and is amenable to in vivo experimental evaluation of viral and host determinants of gammaherpesvirus disease. However, the inability of MHV68 to transform primary murine B cells in culture, the absence of a robust cell culture latency system, and the paucity of MHV68-positive tumor cell lines have limited an understanding of the molecular mechanisms by which MHV68 modulates the host cell during latency and reactivation. To facilitate a more complete understanding of viral and host determinants that regulate MHV68 latency and reactivation in B cells, we generated a recombinant MHV68 virus that encodes a hygromycin resistance protein fused to enhanced green fluorescent protein as a means to select cells in culture that harbor latent virus. We utilized this virus to infect the A20 murine mature B-cell line and evaluate reactivation competence following treatment with diverse stimuli to reveal viral gene expression, DNA replication, and production of progeny virions. Comparative analyses of parental and infected A20 cells indicated a correlation between infection and alterations in DNA damage signaling following etoposide treatment. The data described in this study highlight the potential utility of this new cell culture-based system to dissect molecular mechanisms that regulate MHV68 latency and reactivation, as well as having the potential of illuminating biochemical alterations that contribute to gammaherpesvirus pathogenesis. In addition, such cell lines may be of value in evaluating targeted therapies to gammaherpesvirus-related tumors.
Critical Role of p53 in Histone Deacetylase Inhibitor-Induced Epstein-Barr Virus Zta Expression
Authors: Chang Shih-Shin , Lo You-Chang , Chua Huey-Huey , Chiu Hsin-Yi , Tsai Shu-Chun , Chen Jen-Yang , Lo Kwok-Wai , Tsai Ching-Hwa
Published: May 2008

The tumor suppressor gene p53 plays a central role in the maintenance of normal cell growth and genetic integrity, while its impact on the Epstein-Barr virus (EBV) life cycle remains elusive. We found that p53 is important for histone deacetylase inhibitor-induced EBV lytic gene expression in nasopharyngeal carcinoma cells. Restoration of p53 in p53-null, EBV-infected H1299 cells augments the potential for viral lytic cycle initiation. Evidence from reporter assays demonstrated that p53 contributes to the expression of the immediate-early viral Zta gene. Further analysis indicated that the DNA-binding ability of p53 and phosphorylation of Ser392 may be critical. This study provides the first evidence that p53 is involved in the regulation of EBV lytic cycle initiation.
Brucellosis in the UK: a risk to laboratory workers? Recommendations for prevention and management of laboratory exposure: Table 1
Authors: Reddy S , Manuel R , Sheridan E , Sadler G , Patel S , Riley P
Published: May 2008

Brucellaspp is an uncommon class 3 pathogen isolated in laboratories serving non-endemic areas. This is a report of four recent cases of brucellosis diagnosed at five different London laboratories, and it highlights the need to maintain a high index of suspicion for brucellosis in patients with a history of travel to and/or consumption of unpasteurised foods from endemic areas. A protocol for risk categorisation is proposed, and there is a description of the strategy adopted for serological follow-up of exposed staff and use of postexposure prophylaxis.
Complement deficiency and disease
Authors: Unsworth D J
Published: May 2008

There are approximately 30 serum complement proteins (15% of the globulin fraction), excluding cell surface receptors, and regulatory proteins. Many are manufactured in the liver, and reduced complement is a feature of severe liver failure. Complement proteins contribute to the acute phase response, and high levels are seen in chronic untreated inflammation (eg, rheumatoid arthritis). Once activated, complement is strongly pro-inflammatory. Indeed, almost half of the complement system proteins/receptors play regulatory roles, reflecting the importance of controlling inappropriate activation. This review focuses on disease states arising as a direct consequence of complement deficiency or dysfunction.
Meticillin-resistantStaphylococcus aureushepatic abscess treated with tigecycline: Figure 1
Authors: Khanna N , Inkster T
Published: May 2008

Pyogenic liver abscesses are uncommon in clinical practice and are usually polymicrobial in nature, with members of theEnterobacteriacaefamily often implicated. This report describes the use of tigecycline to treat a liver abscess caused by meticillin-resistantStaphylococcus aureus, which was refractory to therapy with standard antimicrobials.
Large volume “mammotome” biopsy may reduce the need for diagnostic surgery in papillary lesions of the breast
Authors: Carder P J , Khan T , Burrows P , Sharma N
Published: May 2008

Background:

There is currently debate as to whether all papillary lesions diagnosed on breast needle core biopsy (BNCB) require surgical excision. The development of large volume “mammotome” biopsy now permits non-operative removal. Few studies have assessed the usefulness of this approach.

Aim:

To review the pathological and radiological findings in a series of B3 and B4 papillary lesions identified on conventional BNCB with a view to assessing the usefulness of mammotome biopsy as a means of avoiding diagnostic surgery.

Methods:

All BNCBs from 23 June 2005 to 14 August 2007 that contained a B3 or B4 papillary lesion were identified by searching the pathology department records. Follow-up histology and radiological details were obtained.

Results:

34 papillary BNCBs were included in this study: 21 from screen-detected lesions and 13 from patients presenting symptomatically. 31 were classified B3 and three were B4. Four cases included an atypical ductal epithelial proliferation (three B4, one B3). 14 patients had undergone open surgical biopsy, 15 had undergone mammotome excision, and five had had no subsequent procedure. All cases that had undergone mammotome biopsy had not shown atypia on the core, and 13 (87%) proved benign. In two cases the mammotome biopsy was either atypical or malignant, prompting surgery; the biopsy changes deriving from areas of ductal carcinoma in situ arising in the context of multiple intraduct papillomas and both were distinctive mammographically in presenting with large areas of segmental calcification. 11/14 cases that had undergone surgical excision had not shown atypia on the core, and proved benign. All three cases with atypia on the core proved malignant.

Conclusion:

In selected cases, mammotome biopsy may improve sampling of papillary lesions such that malignancy may be excluded without recourse to diagnostic surgery. Mammotome in such cases effectively acts as a therapeutic procedure. This has important implications for symptomatic and breast screening services.
Within-crown cone production patterns dependent on cone productivities in Pinus densiflora: effects of vertically differential, pollination-related, cone-growing conditions
Authors: Iwaizumi Masakazu G. , Ubukata Masatoshi , Yamada Hiroo
Published: May 2008

Although the variations in within-crown cone production have mainly been associated with resource availability, trees with relatively fewer cones allocate more cones to the optimal vertical layer for cone production than their expected resource availability suggests. We investigated the number of cones (NCone) per branch basal area (BBA) and the proportion of cones (PCone) in the three crown layers (upper, middle, and lower) for 72 Pinus densiflora Sieb. et Zucc. clones in 2004 and 2005. We also measured cone characteristics in each layer to infer their resource or pollen availability. Further, in 2006 we conducted pollination experiments for another 19 P. densiflora ramets, manipulating pollen quality (open-pollinated, self-pollinated (selfed), and polycrossed) in their two crown layers (upper and lower), and examined how pollen quality could affect the among-layer differences. Among 72 clones investigated, PCone in the upper crown layer was significantly greater, with a decrease of the total NCone per BBA; at that time, the seed/ovule ratio (S/O) in the upper crown layer cones was generally greater than that found in the middle and lower crown layers. In the pollination experiments, self-pollination resulted in a decreased S/O in the cones, regardless of the crown layer: S/O in the selfed cones, which were pollinated with controlled-quality pollen, did not differ between the upper and lower layers. Clones with relatively fewer cones allocated more resources to producing cones in the optimal cone-producing layer (upper crown layer) than would be expected from their biomass allocation, suggesting that optimal cone production is the result of a pollination-related factor.
Enhanced zinc and cadmium tolerance and accumulation in transgenic Arabidopsis plants constitutively overexpressing a barley gene (HvAPX1) that encodes a peroxisomal ascorbate peroxidase
Authors: Xu Weifeng , Shi Weiming , Liu Feng , Ueda Akihiro , Takabe Tetsuko
Published: May 2008

Ascorbate peroxidase (APX) plays an important role in oxidative stress metabolism in higher plants. To determine the role of APX in protection against excessive-zinc-induced oxidative stress, transgenic Arabidopsis plants constitutively overexpressing a peroxisomal ascorbate peroxidase gene (HvAPX1) from barley were analyzed. In this study, we found that transgenic plants were more tolerant to zinc stress than wild-type plants. Under zinc stress, the concentration of hydrogen peroxide and malondialdehyde accumulation were higher in wild-type plants than in transgenic plants. Therefore, the mechanism of zinc tolerance in transgenic plants may be due to reduced oxidative stress damage. Under zinc stress, the activities of APX were significantly higher in transgenic plants than in wild-type plants. We also found that the zinc accumulation in the shoots were much higher in transgenic plants than in wild-type plants under zinc stress. In addition, we found that compared with wild-type plants, transgenic plants were more tolerant to excessive cadmium stress and accumulated more cadmium in shoots. These results suggest that HvAPX1 plays an important role in zinc and cadmium tolerance, and might be a candidate gene for developing high-biomass tolerant plants for phytoremediation of zinc- and cadmium-polluted environments.
A comparative study of mycorrhizas in several genera of Pyroleae (Ericaceae) from western Canada
Authors: Massicotte H. B. , Melville L. H. , Tackaberry L. E. , Peterson R. L.
Published: May 2008

Genera in the tribe Pyroleae (subfamily Monotropoideae, family Ericaceae) occur as understory plants in northern temperate zones where some form major components of ecosystems. Most have been poorly studied in terms of their association with symbiotic fungi. In this study, colonization patterns of mycorrhizal roots of five members of the Pyroleae ( Pyrola asarifolia Michx., Pyrola chlorantha Sw., Orthilia secunda (L.) House, Chimaphila umbellata (L.) W. Bart., Moneses uniflora (L.) Gray) were explored. Root samples were processed for light, fluorescence, and laser scanning confocal, scanning electron, and transmission electron microscopy, as well as for immunocytochemistry. Roots of all species had enlarged epidermal cells containing hyphal complexes, Hartig nets confined to the epidermis, and mantles. Epidermal cells were penetrated by hyphae originating from the Hartig net at more than one site either along the inner tangential wall or radial walls. The outer tangential wall of epidermal cells of all species, except M. uniflora, was thicker than radial and inner tangential walls and consisted of two layers, the outer containing nonesterified pectins that were labeled with JIM 5 antibodies. Radial walls and inner tangential walls did not label, but cortical cell walls did. Intracellular hyphal complexes developed initially around centrally positioned, enlarged epidermal cell nuclei and, through branching, occupied most of the cell volume. Senescence and degradation of the complexes followed. The fungal species in these symbiotic associations may be important functionally in nutrient exchange, as well as in contributing to broader linkages with other hosts in these plant communities.
Genetic diversity in a collection of borage (Borago officinalis) germplasm
Authors: Sales Ester , Montaner Celia , Muniozguren José M. , Carravedo Miguel , Álvarez José M.
Published: May 2008

The common borage, Borago officinalis L., is of Euro-Mediterranean origin, but is found extensively in the wild. It is also cultivated as a garden plant, crop vegetable, or pharmaceutical herb. Analysis of random amplified polymorphic DNAs (RAPDs) revealed high levels of genetic diversity among 10 borage wild accessions and seven cultivars, which included five white-flowered selections grown in northern Spain for petiole production, and two blue-flowered lines used medicinally. These latter two cultivars and populations, sampled far from the original habitat of the species, were closely related to wild borage populations from northern Europe. The two medicinal cultivars did not differ from each other, while those used for petiole production differed significantly from their Spanish wild relatives. Differences among the 17 populations accounted for 41.4% of the total genetic variability; this value increased to 50.8% when only the 10 wild populations were considered. Population differentiation and within-population variability are discussed in relation to mating system, selection, and conservation practices.
Glyphosate induces transient male sterility in Ipomoea purpurea
Authors: Baucom Regina S. , Mauricio Rodney , Chang Shu-Mei
Published: May 2008

Plant death is the most common effect resulting from the application of glyphosate, the active ingredient in the herbicide Roundup®. Individual seedlings of the morning glory, Ipomoea purpurea L. Roth, however, have been shown to exhibit tolerance to glyphosate, surviving after what should have been a lethal dose. Those that grow and reach reproductive maturity often exhibit deformed anthers within what appear to be normally developed flowers. Ipomoea purpurea has a mixed mating system and normally has hermaphroditic flowers that are capable of both selfing and outcrossing. The deformed anthers do not produce pollen, essentially converting a hermaphroditic flower to a female. Here we describe this morphological change and investigate the reproductive consequences of anther deformation. First, there is phenotypic variation for the propensity of an individual to exhibit male sterility through deformed anthers in response to treatment, but a series of field and greenhouse studies suggest that this variation is not genetic. The male sterility is also transient; within an individual, the frequency of flowers with deformed anthers declines over time. Although flowers with deformed anthers do not produce pollen, we observed mixed effects on female function of such flowers. In the greenhouse, flowers with deformed anthers that were hand-pollinated produced as many seeds as flowers with normal anthers, suggesting no effect on female fertility. In the field, however, plants with a higher proportion of anther deformation set significantly fewer seeds than those untreated, suggesting either reduced female fertility, or a reproductive penalty in flowers with deformed anthers due to the inability to self pollinate. Thus, the presence of this trait could alter the selfing to outcrossing ratio in populations that are sprayed with the herbicide. Individuals that exhibited a higher proportion of anther deformation also produce fewer total flowers than untreated plants, suggesting that anther deformation is part of a suite of responses to damage by glyphosate.
Anamorphs in the Strophariaceae (Basidiomycota, Agaricales)
Authors: Walther Grit , Weiß Michael
Published: May 2008

We describe and illustrate conidiogenesis in 21 species of Strophariaceae sensu Singer in culture, including first reports of conidiogenesis from nine species. Two modes of thallic conidiogenesis were revealed. The first mode, present in Hypholoma capnoides (Fr.) P. Kumm., Hypholoma fasciculare (Fr.) P. Kumm., Hypholoma marginatum (Pers.) J. Schröt., Hypholoma subericaeum (Fr.) Kühner, Hypholoma sublateritium (Schaeff.) Quél., Kuehneromyces mutabilis (Schaeff.) Singer & A.H. Sm., Pholiota lenta (Pers.) Singer, Pholiota lucifera (Lasch) Quél., Pholiota mixta (Fr.) Kuyper & Tjall.-Beuk., Pholiota spumosa (Fr.) Singer, Psilocybe cf. coprophila (Bull.) P. Kumm., Psilocybe inquilina (Fr.) Bres., Psilocybe semilanceata (Fr.) P. Kumm., Psilocybe sp., Stropharia rugosoannulata Farl. ex Murrill, and Stropharia semiglobata (Batsch) Quél., is characterized by straight or often coiled conidiogenous hyphae, not or only slightly sympodially proliferating conidiophores lacking geniculate parts, and hyaline, rod-shaped conidia. Conidiogenesis in Pholiota aurivella (Batsch) P. Kumm., Pholiota gummosa (Lasch) Singer, and Pholiota squarrosa (Batsch) P. Kumm. followed a second mode, distinguished by straight conidiogenous hyphae, sympodially proliferating geniculate conidiophores, and coloured, swollen conidia formed on older mycelia. These two modes also differed concerning the number of nuclei in the conidia. Pholiota alnicola (Fr.) Singer and Pholiota tuberculosa (Schaeff.) P. Kumm. possessed specific modes of conidiogenesis that deviated from the two prevalent modes described above. Careful analysis of anamorph descriptions compiled from literature supports these modes and allows conidia to be distinguished from nondetaching hyphal swellings that have also been designated as conidia in the past.
Induced twining in Convolvulaceae climbing plants in response to leaf damage
Authors: Atala C. , Gianoli E.
Published: May 2008

Plant responses to herbivory include slow changes in growth patterns and biomass distribution. A recent study, however, showed that a convolvulaceous vine began twining sooner around a stake after 25% of the plant was defoliated (damaged). We evaluated whether this induced response is widespread within the Convolvulaceae, and made preliminary studies of its underlying mechanisms. Leaf damage was applied to seven twining vine species from the genera Convolvulus, Calystegia, and Ipomoea. We compared the twining rate (proportion of plants successfully climbing at a given time), growth rate, and twining geometry in the control and in damaged plants. We further evaluated the consequences of jasmonic acid application on the twining rate of Ipomoea purpurea (L.) Roth. Five out of the seven species tested showed an enhanced twining rate after leaf damage. Growth rate did not differ between damaged and undamaged plants in any species. The angle of ascent of the twining stem was lower in damaged plants during the first gyres. Jasmonic acid increased twining rate in I. purpurea, as did leaf damage. The induced twining was not due to increased growth, but to changes in the climbing process, and further mechanistic approaches should consider the jasmonate pathway. Induced twining may be common in the Convolvulaceae, and its occurrence in other families should be tested.
Suberin lamellae of the onion root endodermis: their pattern of development and continuity
Authors: Waduwara C. Ishari , Walcott Shantel E. , Peterson Carol A.
Published: May 2008

In many plant species, suberin lamellae are deposited in the cells of the endodermis. Some cells near the xylem poles tend to remain without these lamellae and are known as “passage cells”. To develop a three-dimensional picture of the pattern of suberin lamella deposition, procedures were developed to isolate large pieces of onion endodermis and to stain their suberin lamellae for various types of microscopy. Sudan red 7B proved satisfactory with white-light, Fluorol yellow and berberine with epifluorescence, and Nile red with confocal laser scanning microscopy (CLSM). Lamella deposition commenced in a few cells 10 mm from the root tip and then proceeded in a scattered manner. However, lamella deposition in more cells (seen 125–155 mm from the root tip) resulted in the formation of longitudinal files of cells with lamellae alternating with files of passage cells. In older regions (255–285 mm from the tip), almost all cells had deposited suberin lamellae, leaving only a few passage cells. At higher magnification, three-dimensional reconstructions of CLSM images of endodermal suberin lamellae revealed that they are perforated by pores all along the roots. Such pores could serve as points for water and ions to enter the cytoplasm of the endodermis.
Change in leaf structure in relation to crown position and size class for tree species within a Sri Lankan tropical rain forest
Authors: Panditharathna P. A.K.A.K. , Singhakumara B. M.P. , Griscom H. P. , Ashton M. S.
Published: May 2008

The purpose of our study was to examine change in leaf structure (anatomy and morphology) through different phases of tree size and crown position within a Sri Lankan rain forest. We selected four late-successional canopy species that represented dominant genera ( Shorea , Mesua ) within an Asian tropical rain forest. All are considered shade-tolerant and capable of growing to maturity beneath closed-canopy late-successional forests. Species within each genus were either restricted to seepages and bottom slopes (valley species) or to upper slopes and ridges (ridge species). The size classes represented (i) seedlings, (ii) saplings, (iii) poles growing beneath closed-canopy conditions, and (iv) trees of the rain forest canopy. Between size classes, leaves were thicker and with higher stomatal densities for canopy trees than for seedling, sapling, and pole size classes. Plasticities for measures of leaf structure were greater for ridge species than valley species; except for cuticle thickness, which showed the opposite trend (valley > ridge). Area, length, and width of leaves attained maxima for the sapling size class for all species. Drip-tip lengths were greatest for seedlings of all species, and least for canopy trees. Trends in leaf structure and morphology dimensions across size classes for late-successional canopy tree species are the same as those trends reported between rain forest species of different habitat strata (e.g., understory shrubs versus upper canopy trees). Our results suggest leaf dimensions could provide robust measures of environment, irrespective of species, or size class of tree.
Tolerance of Brassica nigra to Pieris brassicae herbivory
Authors: Blatt S. E. , Smallegange R. C. , Hess L. , Harvey J. A. , Dicke M. , van Loon J. J.A.
Published: May 2008

Black mustard, Brassica nigra (L.) Koch, is a wild annual species found throughout Europe and fed on by larvae of the large cabbage-white butterfly, Pieris brassicae L. We examined the impact of herbivory from P. brassicae, a gregarious herbivore, on B. nigra grown from wild seed collected locally. In greenhouse studies, the response of B. nigra to four herbivore densities in two developmental stages of the plant was quantified by measuring leaf damage, plant height, days to flowering, silique number, and seed production. Pieris brassicae readily attacked B. nigra leaves, although the timing of the attack did not affect seed production; attacked plants produced as many seeds as as nonattacked plants. Plant height was affected when plants were attacked early, but not later, in development, suggesting a connection between their belowground zone of influence and ability to regain biomass. These results demonstrate that at the herbivore densities and timing of damage studied, B. nigra tolerates folivory from Pieris brassicae through compensation.
Assessing the role of orogen-parallel faulting in post-orogenic exhumation: low-temperature thermochronology across the Norumbega Fault System, Maine
Authors: West David P. , Roden-Tice Mary K. , Potter Jaime K. , Barnard Nellie Q.
Published: May 2008

As a part of a regional effort to determine the extent of low-temperature thermochronological discontinuities across major orogen-parallel faults in northern New England, 41 apatite fission track (AFT) ages and 11 (U–Th)/He ages are used to constrain the ∼65 to 100 °C cooling history of rocks flanking a 160 km long segment of the Norumbega fault system in southern and south-central Maine. These data are used to evaluate the role of this structure in the late Mesozoic and younger exhumation history of the northern Appalachians. AFT ages flanking the fault system range from 159 to 95 Ma and record cooling below ∼100 °C in the late Mesozoic. (U–Th)/He ages from the same region range from 126 to 100 Ma and record cooling below ∼65 °C. Previously published AFT ages from an ∼40 km long segment of the fault system just north of Casco Bay reveal a dramatic time–temperature discontinuity across the structure and suggest kilometre-scale late Mesozoic displacement in this region. However, new AFT and (U–Th)/He ages along the strike of the Norumbega fault system to the northeast and southwest of this discontinuity show no significant differences in late Mesozoic cooling and suggest no significant displacements occurred along these portions of the fault system during this time. Collectively the data suggest differential late Mesozoic reactivation of the Norumbega fault system with the reactivation localized in areas that had previously experienced episodes of vertical displacement in the late Paleozoic (i.e., the “Casco Bay restraining bend”).
Late Quaternary sedimentation on the southwestern Scotian Slope, eastern Canada: relationship to glaciationGeological Survey of Canada Contribution 20070176.
Authors: Hundert Thian , Piper David J.W.
Published: May 2008

The sedimentary record on continental slopes has the potential to preserve a record of glacial retreat on the adjacent continental shelf. The glacial history of the southwestern part of the Scotian Shelf is poorly known. Air-gun and high-resolution sparker profiles and numerous sediment cores up to 10 m long have been used to determine the character of sedimentation on the southwestern Scotian Slope since the last glacial maximum (LGM). Seismic-reflection profiles show that glacial till was deposited at shallow depths on the upper continental slope, and correlation to dated piston cores farther downslope show that this till dates from the LGM. Slope sedimentation at this time was dominated by local ice and deposited as plume fallout and turbidites. Progressively increasing importance of red-brown sediment derived from glacial supply to Laurentian Channel indicates retreat of ice from the shelf edge and diminishing supply of proglacial sediment from the calving embayment in the mid-Scotian Shelf. With the termination of distal proglacial sediment supply, the sedimentation rate diminished rapidly and hemipelagic sedimentation prevailed through the Holocene.
Effects of sand supply on the morphodynamics and stratigraphy of active parabolic dunes, Bigstick Sand Hills, southwestern SaskatchewanGeological Survey of Canada Contribution 20060654.
Authors: Hugenholtz Chris H. , Wolfe Stephen A. , Moorman Brian J.
Published: May 2008

Sand supply is a major controlling factor on parabolic dune form and stratigraphy in inland settings. In this study, aerial photographs, ground-penetrating radar (GPR), and stratigraphic analysis document the morphodynamics of an individual and compound parabolic dune in the Bigstick Sand Hills, southwestern Saskatchewan. Migration rates for the last 60 years are comparable, although the profile morphologies differ, with the individual dune having a more aerodynamic form. Stratigraphic facies are also similar in both dune types, but the overall internal architecture imaged by GPR differs considerably. Configurations of cross-strata parallel to the downwind axis represent dominant foreset development and lee-slope slipface advance of the individual dune, and impeded slipface development of the compound dune. Stratigraphy transverse to the downwind axis represents radial deposition and foreset development at the individual dune, and vertical accumulation at the compound dune. The overall difference in parabolic dune form and stratigraphy is attributed to variations in sand supply, which determine vegetation development and sedimentation processes along the crest and lee slope. Sand supplied from active blowouts upwind of the individual dune inhibits vegetation colonization on the dune, whereas an absence of sand supply upwind of the compound dune leads to high levels of vegetation cover on the dune. Once supply drops below a threshold level, vegetation cover increases, causing sediment deposition and vertical accretion, and ultimately changing dune form. Overall, this study demonstrates that local sand supply and feedback processes are critical to understanding dune development in vegetated, inland settings.
Correlation of mid-Cretaceous granites with source terranes in the northern Canadian CordilleraLithoprobe Publication 1475.
Authors: Morris George A. , Creaser Robert A.
Published: May 2008

This study presents a broad geochemical and isotopic synthesis of mid-Cretaceous granites in the southern Yukon as well as a comparative data set for granites sourced from, and hosted by, accreted terranes in the west through to ancient cratonic rocks in the east. We present data from a traverse perpendicular to the strike of the northern Canadian Cordillera allowing comparison with the growing body of such data derived from the host terranes. Trace elements, specifically the “subduction signature,” allow the discrimination of oceanic verses continental crustal sources. Comparison of isotopic ratios of Sr and, particularly, Nd with published data further refine the correlation of granites with their source terranes. Granites are initially divided based upon their host morphogeological belts, however, our study indicates that the source terranes transcend these traditional boundaries. For Intermontane Belt hosted granites three distinct sources can be identified: an isotopically primitive (Sri, 0.7050; ϵNdT, 2.3 to –1.2), subduction-related source probably associated with the mid-Cretaceous continental margin; an isotopically primitive (Sri, 0.7032 to 0.7035; ϵNdT, 4.2 to 1.4), non-subduction-related source identified as the host Cache Creek terrane; and an isotopically slightly more evolved (Sri, 0.7094 to 0.7101; ϵNdT, 4.5 to –7.3), subduction-related source identified as the host Stikine terrane. Immediately east of the Teslin Tectonic Zone (TTZ), pericratonic Omineca granites (Sri, 0.7032 to 0.7076; ϵNdT, 2.0 to –5.4) do not correlate with their host terranes, but instead show marked similarities with granites immediately to the west of the TTZ suggesting that the same, or similar crustal sources extend further east in the subsurface than previously thought. In the eastern pericratonic Omineca Belt, there is a substantial jump to more evolved isotopic values (Sri, 0.7172 to 0.7354; ϵNdT, –16.6 to –21.7) for granites that extend to the most easterly exposed plutons of the cratonic Omineca Belt. These more isotopically evolved granites correlate with isotopic values for the pericratonic Yukon–Tanana and Cassiar terranes, as well as cratonic North America.
A new Jurassic pliosaur from Melville Island, Canadian Arctic Archipelago
Authors: Sato Tamaki , Wu Xiao-chun
Published: May 2008

A partial skeleton of a plesiosaur (Reptilia: Sauropterygia) from the Hiccles Cove Formation (Middle Jurassic: Callovian) of Melville Island, Canadian Arctic Archipelago, is the first marine reptile fossil with well-preserved skull from the Canadian Arctic and represents a new genus and species of Rhomaleosauridae ( Borealonectes russelli ). The Rhomaleosauridae are a problematic group, and a review of the current status of included taxa is given prior to the description of the Canadian material. The holotype and only known specimen of the new species consists of the skull, anterior cervicals, and right forelimb. The new taxon is characterized by the large prefrontal and the configuration of the postorbital bar in which the postfrontal is excluded from the supratemporal fenestra; these are potentially unique features among rhomaleosaurids. It exhibits a combination of primitive and derived characteristics that are variable among rhomaleosaurids, such as the absence of the dorsomedian foramen and anterior pterygoid vacuity on the palate, and the presence of straight shaft of humerus. The occurrence of this specimen suggests a global distribution of rhomaleosaurids, and it is also significant as one of the few Jurassic plesiosaurs known from North America.
Stable isotope record of the Eifelian–Givetian boundary Kačák–otomari Event (Middle Devonian) from Hungry Hollow, Ontario, Canada
Authors: van Hengstum Peter J. , Gröcke Darren R.
Published: May 2008

The Kačák Event in the Middle Devonian (Eifelian–Givetian (E–G) boundary) is a period of apparent global anoxia coincident with widespread deposition of black shale in hemipelagic, pelagic, and some neritic facies. Conodont biostratigraphy in the North American Appalachian Basin has proven to be problematic in precisely demarcating the E–G boundary. In this study, we show that the E–G boundary may be defined more accurately through isotope stratigraphy (δ13C) in conjunction with a conodont faunal change across this boundary, identified as the Kačák– otomari Event. The Canadian Hamilton Group outcropping in Hungry Hollow, Ontario, is a 22 m sedimentary succession spanning the Middle Devonian. Conodont biostratigraphy for this section makes it difficult to define the E–G boundary, but the otomari Event can be detected. High-resolution isotopic analysis of bulk sedimentary carbonate and organic matter for this succession records a significant negative δ13C excursion (δ13Ccarb = up to 2‰; δ13Corg = ∼3.0‰) that is synchronous with total organic carbon (TOC) values up to 12.5%. We identify this negative δ13C excursion as a result of marine anoxia associated with the Kačák–otomari Event and suggest that the excursion is a global event driven by a source of isotopically light carbon, followed by a productivity event, similar to Mesozoic oceanic anoxic events. Such similarities between Devonian and Mesozoic oceanic anoxic events may become more evident with increased high-resolution isotopic and geochemical investigations of Devonian successions.