bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid and Specific Detection of Amantadine-Resistant Influenza A Viruses with a Ser31Asn Mutation by the Cycling Probe Method
Authors: Suzuki Yasushi , Saito Reiko , Zaraket Hassan , Dapat Clyde , Caperig-Dapat Isolde , Suzuki Hiroshi
Published: November 2009

Amantadine is one of the antiviral agents used to treat influenza A virus infections, but resistant strains have widely emerged worldwide. In the present study, we developed a novel method to detect amantadine-resistant strains harboring the Ser31Asn mutation in the M2 gene based on the cycling probe method and real-time PCR. We also studied the rate of amantadine resistance in the 2007-2008 influenza season in Japan. Two different primer and cycling probe sets were designed for A/H1N1 and A/H3N2 each to detect a single nucleotide polymorphism corresponding to Ser/Asn at residue 31 of the M2 protein. By using nasopharyngeal swabs from patients with influenza-like and other respiratory illnesses and virus isolates, the specificity and the sensitivity of the cycling probe method were evaluated. High frequencies of amantadine resistance were detected among the A/H1N1 (411/663, 62%) and A/H3N2 (56/56, 100%) virus isolates collected from six prefectures in Japan in the 2007-2008 influenza season. We confirmed that the cycling probe method is suitable for the screening of both nasopharyngeal swabs and influenza virus isolates for amantadine-resistant strains and showed that the incidence of amantadine resistance among both A/H1N1 and A/H3N2 viruses remained high in Japan during the 2007-2008 season.
Evidence for Persistence of and Antiviral Resistance and Reassortment Events in Seasonal Influenza Virus Strains Circulating in Cambodia
Authors: Fourment Mathieu , Mardy Sek , Channa Mey , Buchy Philippe
Published: November 2009

The analysis of A/H1N1 and A/H3N2 influenza viruses collected between 2005 and 2008 in Cambodia detected strains resistant to oseltamivir and confirmed widespread resistance to adamantanes. Phylogenetic analyses revealed intrasubtype reassortment, probable reemergence of A/H3N2 viruses in two consecutive seasons, and cocirculation of different lineages in each subtype.
Modification of Small Hepatitis Delta Virus Antigen by SUMO Protein
Authors: Tseng Chung-Hsin , Cheng Tai-Shan , Shu Chiung-Yueh , Jeng King-Song , Lai Michael M. C.
Published: November 2009

Hepatitis delta antigen (HDAg) is a nuclear protein that is intimately involved in hepatitis delta virus (HDV) RNA replication. HDAg consists of two protein species, the small form (S-HDAg) and the large form (L-HDAg). Previous studies have shown that posttranslational modifications of S-HDAg, such as phosphorylation, acetylation, and methylation, can modulate HDV RNA replication. In this study, we show that S-HDAg is a small ubiquitin-like modifier 1 (SUMO1) target protein. Mapping data showed that multiple lysine residues are SUMO1 acceptors within S-HDAg. Using a genetic fusion strategy, we found that conjugation of SUMO1 to S-HDAg selectively enhanced HDV genomic RNA and mRNA synthesis but not antigenomic RNA synthesis. This result supports our previous proposition that the cellular machinery involved in the synthesis of HDV antigenomic RNA is different from that for genomic RNA synthesis and mRNA transcription, requiring different modified forms of S-HDAg. Sumoylation represents a new type of modification for HDAg.
Extensive Host Sharing of Central European Tula Virus
Authors: Schmidt-Chanasit Jonas , Essbauer Sandra , Petraityte Rasa , Yoshimatsu Kumiko , Tackmann Kirsten , Conraths Franz J. , Sasnauskas Kestutis , Arikawa Jiro , Thomas Astrid , Pfeffer Martin , Scharninghausen Jerrold J. , Splettstoesser Wolf , Wenk Matthias , Heckel Gerald , Ulrich Rainer G.
Published: November 2009

To examine the host association of Tula virus (TULV), a hantavirus present in large parts of Europe, we investigated a total of 791 rodents representing 469
Microtus arvalis
and 322
Microtus agrestis
animals from northeast, northwest, and southeast Germany, including geographical regions with sympatric occurrence of both vole species, for the presence of TULV infections. Based on serological investigation, reverse transcriptase PCR, and subsequent sequence analysis of partial small (S) and medium (M) segments, we herein show that TULV is carried not only by its commonly known host
M. arvalis
but also frequently by
M. agrestis
in different regions of Germany for a prolonged time period. At one trapping site, TULV was exclusively detected in
M. agrestis
, suggesting an isolated transmission cycle in this rodent reservoir separate from spillover infections of TULV-carrying
M. arvalis
. Phylogenetic analysis of the S and M segment sequences demonstrated geographical clustering of the TULV sequences irrespective of the host,
M. arvalis
or
M. agrestis
. The novel TULV lineages from northeast, northwest, and southeast Germany described here are clearly separated from each other and from other German, European, or Asian lineages, suggesting their stable geographical localization and fast sequence evolution. In conclusion, these results demonstrate that TULV represents a promiscuous hantavirus with a large panel of susceptible hosts. In addition, this may suggest an alternative evolution mode, other than a strict coevolution, for this virus in its
Microtus
hosts, which should be proven in further large-scale investigations on sympatric
Microtus
hosts.
The Early Gene
hhi1
Reactivates
Heliothis zea
Nudivirus 1 in Latently Infected Cells
Authors: Wu Yueh-Lung , Wu Carol P. , Lee Song-Tay , Tang Han , Chang Chi-Hua , Chen Hong-Hwa , Chao Yu-Chan
Published: November 2009

Heliothis zea
nudivirus 1 (
Hz
NV-1), previously known as Hz-1 virus, is an insect virus able to establish both productive and latent infections in several lepidopteran insect cells. Here, we have cloned and characterized one of the
Hz
NV-1 early genes,
hhi1
, which maps to the HindIII-I fragment of the viral genome. During the productive viral infection, a 6.2-kb
hhi1
transcript was detectable as early as 0.5 h postinfection (hpi). The level of transcript reached a maximum at 2 hpi and gradually decreased after 4 hpi. The transcript was not detectable during the latent phase of viral infection. Upon cycloheximide treatment, much higher levels of
hhi1
transcript were detected throughout the productive viral infection cycle, suggesting that newly synthesized proteins are not needed for the expression of
hhi1
. Nevertheless, viral coinfection can further stimulate the expression of transfected
hhi1
promoter in a plasmid. Transient
hhi1
expression in latently infected cells resulted in a significant increase in virus titer and viral DNA propagation, suggesting that
hhi1
plays a critical role in viral reactivation. Additional experiments showed that six early genes, which possibly function in transcription or DNA replication, were activated in the latent cells upon
hhi1
transfection. Among these six genes,
orf90
and
orf121
expression could be induced by
hhi1
alone without the need for other viral genes. Our discovery should be useful for future mechanistic study of the switches of latent/productive
Hz
NV-1 viral infections.
Germinal Center B Cells Latently Infected with Epstein-Barr Virus Proliferate Extensively but Do Not Increase in Number
Authors: Roughan Jill E. , Torgbor Charles , Thorley-Lawson David A.
Published: November 2009

In this study we show that in long-term persistent infection, Epstein-Barr virus (EBV)-infected cells undergoing a germinal center (GC) reaction in the tonsils are limited to the follicles and proliferate extensively. Despite this, the absolute number of infected cells per GC remains small (average of 3 to 4 cells per germinal center; range, 1 to 9 cells), and only about 38 to 55% (average, 45%) of all GCs carry infected cells. The data fit a model where, on average, cells in the GC divide approximately three times; however, only one progeny cell survives to undergo a further three divisions. Thus, a fraction of cells undergo multiple rounds of division without increasing in numbers; i.e., they die at the same rate that they are dividing. We conclude that EBV-infected cells in the GC undergo the extensive proliferation characteristic of GC cells but that the absolute number is limited either by the immune response or by the availability of an essential survival factor. We suggest that this behavior is a relic of the mechanism by which EBV establishes persistence during acute infection. Lastly, the expression of the viral latent protein LMP1 in GC B cells, unlike in vitro, does not correlate directly with the expression of bcl-2 or bcl-6. This emphasizes our claim that observations made regarding the functions of EBV proteins in cell lines or in transgenic mice should be treated with skepticism unless verified in vivo.
Differential Impact of Immune Escape Mutations G145R and P120T on the Replication of Lamivudine-Resistant Hepatitis B Virus e Antigen-Positive and -Negative Strains
Authors: Amini-Bavil-Olyaee Samad , Vucur Mihael , Luedde Tom , Trautwein Christian , Tacke Frank
Published: November 2009

Immune escape variants of the hepatitis B virus (HBV) represent an emerging clinical challenge, because they can be associated with vaccine escape, HBV reactivation, and failure of diagnostic tests. Recent data suggest a preferential selection of immune escape mutants in distinct peripheral blood leukocyte compartments of infected individuals. We therefore systematically analyzed the functional impact of the most prevalent immune escape variants, the sG145R and sP120T mutants, on the viral replication efficacy and antiviral drug susceptibility of common treatment-associated mutants with resistance to lamivudine (LAM) and/or HBeAg negativity. Replication-competent HBV strains with sG145R or sP120T and LAM resistance (rtM204I or rtL180M/rtM204V) were generated on an HBeAg-positive and an HBeAg-negative background with precore (PC) and basal core promoter (BCP) mutants. The sG145R mutation strongly reduced HBsAg levels and was able to fully restore the impaired replication of LAM-resistant HBV mutants to the levels of wild-type HBV, and PC or BCP mutations further enhanced viral replication. Although the sP120T substitution also impaired HBsAg secretion, it did not enhance the replication of LAM-resistant clones. However, the concomitant occurrence of HBeAg negativity (PC/BCP), sP120T, and LAM resistance resulted in the restoration of replication to levels of wild-type HBV. In all clones with combined immune escape and LAM resistance mutations, the nucleotide analogues adefovir and tenofovir remained effective in suppressing viral replication in vitro. These findings reveal the differential impact of immune escape variants on the replication and drug susceptibility of complex HBV mutants, supporting the need of close surveillance and treatment adjustment in response to the selection of distinct mutational patterns.
Structural Studies of the Sputnik Virophage
Authors: Sun Siyang , La Scola Bernard , Bowman Valorie D. , Ryan Christopher M. , Whitelegge Julian P. , Raoult Didier , Rossmann Michael G.
Published: November 2009

The virophage Sputnik is a satellite virus of the giant mimivirus and is the only satellite virus reported to date whose propagation adversely affects its host virus' production. Genome sequence analysis showed that Sputnik has genes related to viruses infecting all three domains of life. Here, we report structural studies of Sputnik, which show that it is about 740 Å in diameter, has a T=27 icosahedral capsid, and has a lipid membrane inside the protein shell. Structural analyses suggest that the major capsid protein of Sputnik is likely to have a double jelly-roll fold, although sequence alignments do not show any detectable similarity with other viral double jelly-roll capsid proteins. Hence, the origin of Sputnik's capsid might have been derived from other viruses prior to its association with mimivirus.
Host and Viral Translational Mechanisms during Cricket Paralysis Virus Infection
Authors: Garrey Julianne L. , Lee Yun-Young , Au Hilda H. T. , Bushell Martin , Jan Eric
Published: November 2009

The dicistrovirus is a positive-strand single-stranded RNA virus that possesses two internal ribosome entry sites (IRES) that direct translation of distinct open reading frames encoding the viral structural and nonstructural proteins. Through an unusual mechanism, the intergenic region (IGR) IRES responsible for viral structural protein expression mimics a tRNA to directly recruit the ribosome and set the ribosome into translational elongation. In this study, we explored the mechanism of host translational shutoff in
Drosophila
S2 cells infected by the dicistrovirus, cricket paralysis virus (CrPV). CrPV infection of S2 cells results in host translational shutoff concomitant with an increase in viral protein synthesis. CrPV infection resulted in the dissociation of eukaryotic translation initiation factor 4G (eIF4G) and eIF4E early in infection and the induction of deIF2α phosphorylation at 3 h postinfection, which lags after the initial inhibition of host translation. Forced dephosphorylation of deIF2α by overexpression of dGADD34, which activates protein phosphatase I, did not prevent translational shutoff nor alter virus production, demonstrating that deIF2α phosphorylation is dispensable for host translational shutoff. However, premature induction of deIF2α phosphorylation by thapsigargin treatment early in infection reduced viral protein synthesis and replication. Finally, translation mediated by the 5′ untranslated region (5′UTR) and the IGR IRES were resistant to impairment of eIF4F or eIF2 in translation extracts. These results support a model by which the alteration of the deIF4F complex contribute to the shutoff of host translation during CrPV infection, thereby promoting viral protein synthesis via the CrPV 5′UTR and IGR IRES.
Detection of mutations in thegyrA gene in fluoroquinolone resistanceSalmonella entericaserotypestyphiandparatyphiA isolated from the Infectious Diseases Hospital, Kuwait
Authors: Dimitrov T , Dashti A A , Albaksami O , Jadaon M M
Published: November 2009

Background:

Enteric fever due toSalmonella entericais a major health problem, and fluoroquinolones such as ciprofloxacin are mostly the antibiotic of choice for treatment. Resistance to ciprofloxacin has been noticed to increase due to the emergence of new mutations in the bacterial DNA.

Aims:

To explore the fluoroquinolone resistance and molecular characterisation of reduced quinolone susceptibility inS typhiandS paratyphiA in Kuwait.

Methods:

136 clinical isolates ofS typhiand 40 ofS paratyphiA were collected over five years. The antimicrobial susceptibility was studied by various methods. DNA sequencing of gyrA, gyrB, parC and parE genes was performed in 31 isolates.

Results:

There was a substantial difference in MIC range between the two serotypes, with the most common MIC forS typhibeing 0.25 mg/l and forS paratyphiA being 1 mg/l. The proportion of nalidixic acid resistant strains increased gradually over the years. These strains had a significantly higher range of MIC of ciprofloxacin (0.023 mg/l to 1.0 mg/l) compared to the nalidixic acid sensitive strains (0.0016 mg/l to 0.125 mg/l). DNA sequencing of gyrA gene showed the presence of three different point mutations: Ser83→Phe in 17 strains, Ser83→Leu in 3 strains and Asp87→Asn in 6 strains. No mutations in the other genes were found.

Conclusions:

It is very important to keep searching for new mutations and continuously monitor drug resistance in different parts of the world in order to efficiently manage cases with enteric fever.
Hybrid SPECT/CT: the end of “unclear” medicine
Authors: Patel C N , Chowdhury F U , Scarsbrook A F
Published: November 2009

The emergence of hybrid imaging, combining anatomical computed tomography (CT) and functional scintigraphic imaging has increased the armoury of techniques available to image disease. Single photon emission computed tomography/CT (SPECT/CT) is a dual modality technique which increases the sensitivity and specificity of existing radionuclide imaging and helps characterise equivocal lesions detected by other imaging methods. In addition to the many established clinical applications for SPECT/CT, there are new clinical uses emerging in a spectrum of benign and malignant diseases. In this article, we will discuss the established and emerging uses of hybrid SPECT/CT and illustrate the incremental value of the technique in a variety of clinical applications.
Studies of metal uptake, especially iron, into protein bodies of Capsella and Lycopersicon seeds
Authors: Spitzer Ernest , Lott John N. A. , Vollmer Catherine M.
Published: November 2009

Energy dispersive X-ray analysis was used to investigate metal uptake into the globoid crystals of Capsella and Lycopersicon seeds. Capsella seeds were taken from the curbside of a major roadway where metal contamination was highest, 5 m from the curb where less metal contamination occurs, and from an area well away from any roadways. Globoid crystals in Capsella protein bodies generally contained P, K, Ca, and Mg. No uptake of Pb or any other toxicant metals into the globoid crystals was found. Globoid crystals from the radicles and cotyledons of seeds produced by plants growing near the curb generally contained Fe whereas seeds of plants growing 5 m back from the curb contained traces of Fe in globoid crystals in certain tissues. Seeds of plants growing farthest from any roadway contained no Fe in their globoid crystals. Seeds of Lycopersicon were grown in metal-contaminated soil obtained near a smelter, a 1:1 mixture of this contaminated soil and regular potting soil, and a control. Globoid crystals from control seeds generally contained P, K, and Mg, while Ca, Mn, and (or) Fe were present occasionally. Control endosperm globoid crystals did not contain Fe. No pollutant metals were taken up into the globoid crystals. Iron which was present in the contaminated soil was found in the globoid crystals of the endosperm in those seeds obtained from plants grown in contaminated soil. Also, although Fe-containing globoid crystals were specifically located throughout the embryo in control seeds, there was no evidence that seeds of plants grown in contaminated soil contained more Fe in these areas.
A survey of epicuticular waxes among genera of Triticeae. 2. Chemistry
Authors: Tulloch A. P. , Baum Bernard R. , Hoffman L. L.
Published: November 2009

During an extensive investigation of the composition of epicuticular waxes from members of the tribe Triticeae, 174 specimens of 123 species from 22 genera have been analyzed. Alcohol content and chain length, β-diketone, hydroxy-β-diketone, and oxo-β-diketone content and structure, and hydrocarbon and ester content have been determined. Sixteen characters have been derived from the results and examined by principal-coordinate and cluster analyses. The results showed considerable uniformity within the tribe; either alcohols, principally hexacosanol or octacosanol, or β -diketones were the major constituents of the wax, hydrocarbons and esters were always minor constituents. When genera were compared, Aegilops, Hordeum, and Roegneria were found to be more uniform than Agropyron, Elymus, Elytrigia, and Leymus but distinctive differences between most of the major genera were observed.
Injury to aspen (Populus tremuloides) exposed to airborne salt from potash mines in Saskatchewan
Authors: Townley-Smith L. J. , Redmann R. E.
Published: November 2009

Branch tip death, leaf chlorosis and necrosis, leaf size, and leaf chloride content were measured in samples of aspen (Populus tremuloides Michx.) collected from stands around nine potash mine–refinery complexes in Saskatchewan. Branch tip death and leaf chloride content were highest in stands near the mines. The proportion of injured leaves and variance in leaf size were highest in the region of maximum branch damage close to the mines. Most damage was confined to areas extending up to 6 km northwest and southeast of the mines and up to 3 km northeast and southwest. This pattern was related to prevailing wind directions. Variability in injury probably results from variation in salt dust emissions, meteorological conditions, and plant susceptibility. Branch tip death is the best indicator of injury from airborne salt.
Utilization of carbon and nitrogen compounds by Frankia in synthetic media and in root nodules of Alnus glutinosa, Hippophaë rhamnoides, and Datisca cannabina
Authors: Akkermans Antoon D. L. , Roelofsen Wim , Blom Jan , Huss-Danell Kerstin , Harkink Reint
Published: November 2009

Frankia AvcI1 utilizes only Tweens and fatty acids as sole carbon sources but N2, NH4+, NO3−, and various amino acids as nitrogen sources. The yield in propionate medium was increased by CO2. Cells grown in media with Tween 80 or acetate as C source contain the glyoxylate-cycle enzymes, isocitrate lyase and malate synthase. These enzymes are repressed in cells grown in media with propionate as well as in the symbiotic stage of Frankia in the nodules. The nature of the carbon compounds utilized by Frankia in the nodule symbiosis is discussed. Vesicle clusters derived from root nodules of Alnus respire succinate (however, only at a very low rate, which probably is due to damage of the membrane of the endophyte). Vesicle clusters derived from Alnus and Hippophaë nodules also take up O2 when supplied with a mixture of glutamate, malate, and NAD, indicating that the reduction equivalents could be transported from the host to the endophyte via the malate–aspartate shuttle. Vesicle clusters derived from Datisca respire succinate at a relatively high rate. Electron micrographs of Datisca nodules showed the presence of clusters of mitochondria embedded in the endophyte material, which might be of importance in the energy supply of the endophyte. These mitochondria are partly disintegrated during the preparation of the vesicle-cluster suspensions.
Root hair deformation in the infection process of Alnus rubra
Authors: Berry Alison M. , Torrey John G.
Published: November 2009

Structural and cell developmental studies of root hair deformation in Alnus rubra Bong. (Betulaceae) were carried out following inoculation with the soil pseudomonad Pseudomonas cepacia 85, alone or in concert with Frankia, and using axenically grown seedlings. Deformational changes can be observed in elongating root hairs within 2 h of inoculation with P. cepacia 85. These growing root hairs become branched or multilobed and highly modified from the single-tip growth of axenic root hairs. The cell walls of deformed hairs are histologically distinctive when stained with the fluorochrome acridine orange. Filtrate studies using P. cepacia 85 suggest that the deforming substance is not a low molecular weight compound. Root hair deformation and the associated wall histology are host specific in that Betula root hairs show none of these responses when grown and inoculated in the experimental conditions described. The bacterially induced changes in root hair cell walls during deformation may create a chemically and physically modified substrate for Frankia penetration, and the deformation itself may serve to entrap and enclose the filamentous organism, allowing wall dissolution and entry. Thus these events represent a complex host response as a precondition to successful nodulation.
Hemoglobins in the nitrogen-fixing root nodules of actinorhizal plants
Authors: Tjepkema John D.
Published: November 2009

The occurrence of high concentrations of hemoglobins in the root nodules of Casuarina cunninghamiana Miq. and Myrica gale L. has been confirmed using spectrophotometry of nodule segments. In an atmosphere of N2, absorption bands were observed at approximately 560 nm, while in O2, bands were found at 540 and 580 nm. These bands were rapidly reversed when O2 and N2 were interchanged in the gas phase. In the presence of CO, absorption bands at 540 and 570 nm were observed. Lower concentrations of hemoglobins were present in nodules of Comptonia peregrina (L.) Coult., Alnus rubra Bong., and Elaeagnus angustifolia L. Zero to trace amounts were found in Ceanothus americanus L. and Datisca glomerata (Presl.) Baill. Preparation of a crude extract from nodules of C. cunninghamiana indicated that the hemoglobin is in a soluble form. Other workers may have failed to observe hemoglobins in actinorhizal nodules because of the low concentrations in many nodules or because hemoglobin is restricted to the tissue containing the active endophyte, and this tissue occupies a relatively small fraction of the nodule volume.
A new Morrisographium-like species with appendaged conidia assigned to the genus Conicomyces
Authors: Illman Wm. I. , White George P.
Published: November 2009

An apparently new dark synnematous hyphomycete with apically appendaged phragmoconidia is described as a second species of the genus Conicomyces. Facets of its ontogeny and biology are discussed.
The dark synnematous hyphomycete genus Morrisographium: described species transferred from Sphaeronaema, Cornularia, Phragmographium, and Arthrobotryum
Authors: Illman Wm. I. , White George P.
Published: November 2009

Five species congeneric with Morrisographium persicae (Schw.) Illman & G. P. White (=M. pilosum (Earle) Morelet) are transferred; viz., Arthrobotryum fusisporium A.L. Sm., Sphaeronaema boudieri Ch. Richon, Sphaeronaema hispidulum Ell. non Cda., Cornularia ulmicola Ell. & Ev., and Phragmographium ulmi Morris. Comparative studies of the accepted species are presented and a key to them is provided. Certain excluded taxa are discussed.
Injury within the crown of winter wheat seedlings after freezing and icing stress
Authors: Tanino Karen K. , McKersie Bryan D.
Published: November 2009

The cells in the crown of winter wheat cv. Fredrick critical for the survival of freezing and icing stress were identified using tetrazolium staining as a viability test. In acclimated seedlings, a freezing stress which lowered regrowth (−12 °C) also lowered tetrazolium staining in the vascular transition zone in the basal portion of the crown but generally did not affect the staining of the apical meristem. The majority of cells in the crown, including the apical meristem, were able to reduce tetrazolium after a lethal freezing stress. Thus, survival was limited by the freezing tolerance of a relatively small number of cells in the basal region of the crown. These observations were confirmed using plasmolysis and mitotic figures as alternative indicies of viability. No significant variability was observed among winter wheat cultivars. However, in seedlings not acclimated to freezing stress, there was quite a different pattern of injury. In these seedlings, the sensitivity of the apical and basal regions to freezing was similar. Thus, these two regions appeared to differentially acclimate and the cells of the apical meristem developed greater cold hardiness than that of the basal area. After a lethal icing stress, all regions within the crown were able to reduce tetrazolium, but the crown was unable to regrow. The ability to reduce tetrazolium was gradually lost during the regrowth period. Unlike freezing stress, no differential sensitivity was observed within the crown, and there was no variability among the cultivars of winter wheat examined.
Morphology, element composition, and response to acids and oxidizing agents of the haustorial neckband of Uromyces phaseoli var. vignae
Authors: Heath Michèle C. , Allen Frances H. E.
Published: November 2009

In unstained sections of glutaraldehyde-fixed, nonsporulating colonies of the cowpea rust fungus Uromyces phaseoli var. vignae, the most common type of haustorial neckband comprised a single, electron-opaque, periodic acid sensitive ring encircling the neck of the haustorium. Energy-dispersive X-ray (EDX) analysis revealed such rings to be particularly rich in iron and phosphorus. Neckbands in similarly fixed sporulating colonies usually consisted of two rings. The ring towards the haustorial body was rich in iron, phosphorus, and calcium, with minor, variable amounts of manganese and potassium. Fe:P ratios were lower than those recorded for single-ring neckbands, apparently because of a relative increase in the amount of phosphorus. The iron-rich ring was removed by periodic acid treatment, in contrast to the second ring which was insensitive to periodic acid and was shown by EDX analysis to be rich in silicon. In stained sections, neckbands were associated with a differentiated region of the haustorial neck wall, and the circumscribed fungal cytoplasm, which was present before the neckband developed. Single-ring neckbands in unstained sections from a glutaraldehyde – osmium tetroxide fixed nonsporulating colony resembled those from tissue fixed in glutaraldehyde alone with respect to appearance, element composition, and sensitivity to periodic acid. In tissue fixed with or without osmium tetroxide, an increase in the electron translucency of the neckband was induced in unstained material by treating sections with acetic or hydrochloric acid, or by conventional staining with uranyl acetate and lead citrate. Such an effect was only rarely induced by hydrogen peroxide treatment. Acid-or stain-induced erosion of the neckband often was associated with the removal of osmiophilic material from the adjacent fungal and host cytoplasm. The results suggest that the neckband region of the haustorial neck represents an area of complex, and changeable, differentiation of fungus, plant, and extrahaustorial matrix.
Photosynthetic response to growth temperature and CO2 enrichment in two species of C4 grasses
Authors: Potvin Catherine , Strain Boyd R.
Published: November 2009

Plants of Echinochloa crus-galli from Québec, North Carolina, and Mississippi and of Eleusine indica from Mississippi were grown under three thermoperiods (28:22, 24:18, 21:15 °C) and two atmospheric CO2 concentrations (350 and 675 μL ∙ L−1). CO2 enrichment induced an increase in net photosynthesis and in dark respiration for all populations. Neither conductance, transpiration, nor the transpiration/photosynthesis ratio were affected by CO2 enrichment. Plants showed higher photosynthetic and dark respiration rates when grown in warm regimes. Stomatal conductance did not vary with growth temperature. Cool-adapted plants from Québec maintained the overall highest net photosynthesis and respiration. Plants originating from warm areas had a weaker acclimation potential to low temperature than those from cool environments.
Acclimation of winter rye to cold-hardening temperatures results in an increased capacity for photosynthetic electron transport
Authors: Huner N. P. A.
Published: November 2009

Photosynthetic electron transport and its partial reactions were measured as a function of light intensity and temperature in isolated chloroplasts from cold-hardened and unhardened rye (Secale cereale L. cv. Puma). Chloroplasts from cold-hardened rye plants exhibited light-saturated rates for whole chain electron transport that were about 1.4-fold higher at 25 °C than those observed in chloroplasts from unhardened rye plants. This was correlated with light-saturated rates of electron transport through photosystem I that were 1.6-fold higher in cold-hardened chloroplasts than in unhardened chloroplasts. These results could not be attributed to a differential uncoupling of electron transport, nor to a differential production of a superoxide free radical which would stimulate net O2 consumption. Electron transport through photosystem II of cold-hardened and unhardened chloroplasts exhibited a differential sensitivity to temperature. The ratio of light-saturated rates in cold-hardened chloroplasts to light-saturated rates in unhardened chloroplasts increased from 0.87 to 1.40 when the temperature was decreased from 26 to 4.5 °C. The locus of this differential temperature sensitivity appeared to reside on the O2 evolving side of photosystem II prior to the site of electron donation by diphenylcarbazide. On the basis of the estimates of the number of photons required for half the maximal rates of electron transport, it was concluded that the efficiency of light utilization by photosystem I and II was unaffected by growth temperature. However, the estimated efficiency for light utilization did increase with a decrease in reaction temperature for chloroplasts from both cold-hardened and unhardened ‘Puma’ rye. Thus, it is concluded that growth at cold-hardening temperatures resulted in an increase in the capacity for photosynthetic electron transport, but did not affect the quantum efficiency for this process.
The role of myrosinase in the development of toxicity toward Nematospora in mustard seed
Authors: Holley R. A. , Jones J. D.
Published: November 2009

The toxicity of contaminated mustard seed toward Nematospora yeast was due to the action of endogenous myrosinase upon the glucosinolates, sinigrin from Brassicajuncea, and sinalbin from B. hirta seeds to produce toxic hydrolysis products. Allyl isothiocyanate from sinigrin was lethal at 20–35 μg/mL while p-hydroxybenzyl alcohol and p-hydroxybenzoic acid from sinalbin were toxic at >600 and >800 μg/mL, respectively. Two cultivars of rapeseed (B. campestris cv. Echo and cv. Candle) contained only trace amounts of sinigrin and sinalbin and were not toxic to the yeast. The activation of myrosinase during germination of oriental and yellow mustard and the production of toxic hydrolytic compounds may limit the spread of infection by reducing the reservoir of viable yeast in the seed. No evidence was obtained to suggest a role for these toxic products in resistance of the plant to invasion by Nematospora.
Pacific yew dominance in tall forests, a classification dilemma
Authors: Crawford Rex C. , Johnson Frederic D.
Published: November 2009

A review and discussion of the confusing terminology for units designating variation in vegetation associations (habitat types) are presented. In portions of the northern Rocky Mountains, the short tree Taxus brevifolia expresses climax sociological dominance over tall conifers. The synecology of communities dominated by T. brevifolia is presented, concluding that associations and not phases are the appropriate interpretation. Binomials now used in forest classifications conceal information on community structure and composition. Trinomials are proposed.
Xylem water potentials and hydraulic conductances in eight species of ferns
Authors: Calkin Howard W. , Gibson Arthur C. , Nobel Park S.
Published: November 2009

Water potentials, flow rates, and anatomy of xylary elements were studied in eight species of ferns to assess the physical constraints that xylem structure presents to water flow. Comparisons were made among ferns of different leaf morphology as well as between a fern with vessels and ferns with tracheids only. Hydraulic conductance was measured by forcing a solution through excised plant segments. These hydraulic conductances were in close agreement with conductances calculated from water potential gradients and flows measured in intact plants. In three species, backflushing excised segments by forcing a basipetal flow increased subsequently measured conductances two- to six-fold, indicating that the xylem of these three species was partially blocked in intact plants. Hagen–Poiseuille estimates of conductance based on xylary element diameters were 1.8–2.7 times the conductances measured for excised segments. Hydraulic conductances of tracheids and vessels of ferns thus deviate from those of ideal capillaries of similar diameter to about the same extent as has been reported for tracheids in conifers and for vessels in dicotyledons.
Wave disturbance on lakeshores and the within-lake distribution of Ontario's Atlantic coastal plain flora
Authors: Keddy Paul A.
Published: November 2009

Although water level fluctuations may explain the persistence of Atlantic coastal plain species in certain Georgian Bay lakes, they cannot explain the within-lake distribution of this flora. To test whether the within-lake distribution of these species was correlated with disturbance from waves, 25 transects were quantitatively sampled along an exposure gradient in Axe Lake, Ontario. The proportion of Atlantic coastal plain species in a transect increased significantly with exposure (p < 0.01). Total frequency of Atlantic coastal plain species reached a maximum at an intermediate level of exposure. Analysis of substrate samples showed that the exposure gradient is a multivariate gradient including not only biomass removal by waves, but sorting of the shoreline substrate. The coarse, nutrient poor sites on exposed shores may allow the persistence of Atlantic coastal plain species in at least two different ways. Their physiological tolerance limits may be narrowly specialized on exposed shorelines. Alternatively, their physiological tolerances may include a broad range of shoreline types, but competition restricts them to those sites least suitable for other species.
THE NORMAL STATE HALL EFFECT IN NdBa2-xLaxCu3O7-δ: EVIDENCE FOR HOLE LOCALIZATION BY LA DOPING
Authors: GHORBANI S. R. , ABRINAEY F.
Published: November 2009

The transport properties of sintered samples of NdBa 2-x La x Cu 3 O 7-δ with 0 ≤ x ≤ 0.3 have been studied in the normal state by Hall effect measurements. The Hall coefficient, RH is positive in the normal state and increases with increasing La doping concentration over the whole temperature range from the critical temperature, Tc, up to room temperature. The results for the Hall coefficient as a function of temperature and doping concentration were analyzed within the phenomenological narrow band and Anderson models. A good agreement between models and data was obtained. As in the phenomenological narrow band model, the band widths increase with increasing doping concentration. As in the Anderson model, the Hall angle is proportional to T2 over the whole measured temperature range for all samples. The obtained results for both models supported the view that La doping introduces electronic disorder into the CuO 2 planes. The tendency towards localization is driven by electronic disorder. In addition to hole filling, the localization is another reason for the decreasing superconducting critical temperature in these samples.
SELF-DUAL VORTICES IN THE FRACTIONAL QUANTUM HALL SYSTEM
Authors: ZHANG XIN-HUI , DUAN YI-SHI , LIU YUXIAO , ZHAO LI
Published: November 2009

Based on the ϕ-mapping theory, we obtain an exact Bogomol'nyi self-dual equation with a topological term, which is ignored in traditional self-dual equation, in the fractional quantum Hall system. It is revealed that there exist self-dual vortices in the system. We investigate the inner topological structure of the self-dual vortices and show that the topological charges of the vortices are quantized by Hopf indices and Brouwer degrees. Furthermore, we study the branch processes in detail. The vortices are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of the vector field ϕ.
TEMPERATURE DEPENDENCE OF THE DAMPING CONSTANT CLOSE TO THE I–II PHASE TRANSITION IN s-TRIAZINE
Authors: KAVRUK D. , YURTSEVEN H.
Published: November 2009

The damping constant is calculated here at various temperatures for the Raman mode II in s-triazine using the soft mode–hard mode coupling model. The temperature dependence of the order parameter is used as the input data to calculate the damping constant of the Raman mode studied in this coupling model for s-triazine close to the I–II transition (Tc = 198 K ). The soft mode–hard mode coupling model which considers the coupling of the soft acoustic mode with the optic modes in s-triazine, is fitted to the observed halfwidths of the Raman mode II close to the I–II phase transition in this crystal.
CONFORMATIONAL PREFERENCES OF N-ACETYL–GLYCINE–GLYCINE–N′-METHYLAMIDE: A THEORETICAL STUDY
Authors: LEE HO-JIN , PARK HYUN-MEE , LEE KANG-BONG
Published: November 2009

The conformational preferences of peptide models have been investigated to understand the protein folding mechanism and to develop the force field. Here, we report the minimum energy conformations for a model peptide, N-acetyl–glycine–glycine–N′-methylamide ( Ac–1Gly–2Gly–NHMe(I) ) at the HF/3-21G, HF/6-31G*, and the B3LYP/6-31G* level of theory. At the B3LYP/6-31G* level, the 31 minima were identified and the 10 β-turn structures among the minima were observed in gas-phase. The conformational preferences of Gly residue in the model peptide, I depend on its relative position and conformation of neighboring Gly residue. The Gly residue in this model dipeptide has an asymmetric energy profile as one of Gly residue adopts a specific conformation. This study sheds some lights on understanding the unique conformational preferences of Gly residue in protein including two consecutive Gly residues.
Protein expression profiling of lens epithelial cells from Prdx6-depleted mice and their vulnerability to UV radiation exposure
Authors: Kubo Eri , Hasanova Nailia , Tanaka Yukie , Fatma Nigar , Takamura Yoshihiro , Singh Dhirendra P. , Akagi Yoshio
Published: November 2009

Oxidative stress is one of the causative factors in progression and etiology of age-related cataract. Peroxiredoxin 6 (Prdx6), a savior for cells from internal or external environmental stresses, plays a role in cellular signaling by detoxifying reactive oxygen species (ROS) and thereby controlling gene regulation. Using targeted inactivation of the Prdx6 gene, we show that Prdx6-deficient lens epithelial cells (LECs) are more vulnerable to UV-triggered cell death, a major cause of skin disorders including cataractogenesis, and these cells display abnormal protein profiles. PRDX6-depleted LECs showed phenotypic changes and formed lentoid body, a characteristic of terminal cell differentiation and epithelial-mesenchymal transition. Prdx6−/− LECs exposed to UV-B showed higher ROS expression and were prone to apoptosis compared with wild-type LECs, underscoring a protective role for Prdx6. Comparative proteomic analysis using fluorescence-based difference gel electrophoresis along with mass spectrometry and database searching revealed a total of 13 proteins that were differentially expressed in Prdx6−/− cells. Six proteins were upregulated, whereas expression of seven proteins was decreased compared with Prdx6+/+ LECs. Among the cytoskeleton-associated proteins that were highly expressed in Prdx6-deficient LECs was tropomyosin (Tm)2β. Protein blot and real-time PCR validated dramatic increase of Tm2β and Tm1α expression in these cells. Importantly, Prdx6+/+ LECs showed a similar pattern of Tm2β protein expression after transforming growth factor (TGF)-β or H2O2 treatment. An extrinsic supply of PRDX6 could restore Tm2β expression, demonstrating that PRDX6 may attenuate adverse signaling in cells and thereby maintain cellular homeostasis. Exploring redox-proteomics ( Prdx6−/−) and characterization and identification of abnormally expressed proteins and their attenuation by PRDX6 delivery should provide a basis for development of novel therapeutic interventions to postpone ROS-mediated abnormal signaling deleterious to cells or tissues.
Voiding function in obese and type 2 diabetic female rats
Authors: Gasbarro Gregory , Lin Dan Li , Vurbic Drina , Quisno Amanda , Kinley Bruce , Daneshgari Firouz , Damaser Margot S.
Published: November 2009

The effects of obesity and type 2 diabetes (DMII) on the lower urinary tract (LUT) were characterized by evaluating voiding function and anatomy in female Zucker diabetic fatty (ZDF) rats. Age-matched female virgin rats were separated into three experimental groups: Zucker lean rats (control; normal diet, n = 22), ZDF rats (obese+nondiabetic; low-fat diet, n = 22), and ZDF rats (obese+diabetic; high-fat diet, n = 20). Rats were placed on their specified diet for 10 wk before urodynamic LUT evaluation. A suprapubic catheter was implanted 2 days before urodynamic studies. Voiding function was evaluated by cystometric and leak point pressure (LPP) testing. The bladder, urethra, and vagina were immediately excised for qualitative histological evaluation. Compared with control rats, obese+nondiabetic and obese+diabetic rats had significantly decreased contraction pressure ( P = 0.003) and increased cystometric filling volume ( P < 0.001). Both obese groups exhibited significantly higher voided volumes ( P = 0.003), less frequent urinary events ( P < 0.001), and increased residual volumes ( P = 0.039). LPP studies showed a nonsignificant decrease in LPP ( P = 0.075) and baseline pressure ( P = 0.168) in both obese groups compared with control. Histology of the external urethral sphincter in obese rats showed increased fibrosis, leading to disruption of the skeletal muscle structure compared with control. Additionally, the bladder wall of the obese+nondiabetic and obese+diabetic rats demonstrated edema and vasculopathy. Voiding dysfunction was evident in both obese groups but with no significant differences due to DMII, suggesting that voiding dysfunction in DMII may be attributable at least in part to chronic obesity.
Intrinsic Functional Connectivity As a Tool For Human Connectomics: Theory, Properties, and Optimization
Authors: Van Dijk Koene R. A. , Hedden Trey , Venkataraman Archana , Evans Karleyton C. , Lazar Sara W. , Buckner Randy L.
Published: November 2009

Resting state functional connectivity MRI (fcMRI) is widely used to investigate brain networks that exhibit correlated fluctuations. While fcMRI does not provide direct measurement of anatomic connectivity, accumulating evidence suggests it is sufficiently constrained by anatomy to allow the architecture of distinct brain systems to be characterized. fcMRI is particularly useful for characterizing large-scale systems that span distributed areas (e.g., polysynaptic cortical pathways, cerebro-cerebellar circuits, cortical-thalamic circuits) and has complementary strengths when contrasted with the other major tool available for human connectomics—high angular resolution diffusion imaging (HARDI). We review what is known about fcMRI and then explore fcMRI data reliability, effects of preprocessing, analysis procedures, and effects of different acquisition parameters across six studies ( n = 98) to provide recommendations for optimization. Run length (2–12 min), run structure (1 12-min run or 2 6-min runs), temporal resolution (2.5 or 5.0 s), spatial resolution (2 or 3 mm), and the task (fixation, eyes closed rest, eyes open rest, continuous word-classification) were varied. Results revealed moderate to high test-retest reliability. Run structure, temporal resolution, and spatial resolution minimally influenced fcMRI results while fixation and eyes open rest yielded stronger correlations as contrasted to other task conditions. Commonly used preprocessing steps involving regression of nuisance signals minimized nonspecific (noise) correlations including those associated with respiration. The most surprising finding was that estimates of correlation strengths stabilized with acquisition times as brief as 5 min. The brevity and robustness of fcMRI positions it as a powerful tool for large-scale explorations of genetic influences on brain architecture. We conclude by discussing the strengths and limitations of fcMRI and how it can be combined with HARDI techniques to support the emerging field of human connectomics.