bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogeography of native ploidy levels and invasive tetraploids of Solidago gigantea
Authors: SCHLAEPFER DANIEL R. , EDWARDS PETER J. , WIDMER ALEX , BILLETER REGULA
Published: November 2008

Ploidy level is an important aspect of the genetic makeup of a plant, and can strongly influence ecological characteristics such as invasiveness. We used a phylogeographical approach to elucidate the history of polyploidization and colonization success of diploid and tetraploid Solidago gigantea Aiton (Asteraceae) within its native range in North America. We were also able to identify the probable source material of the haplotype lineages invasive in Europe and Asia, where only tetraploid plants occur. To do this, we sequenced 1275 bp of chloroplast intergenic spacer DNA in 268 individuals from 57 populations. In addition, we performed a crossing experiment, which supported the hypothesis that chloroplast inheritance in this species is maternal. The phylogeographical analysis showed a complex pattern of 20 haplotypes of diploid and tetraploid plants. In North America, we found significant differentiation among regions, private haplotypes, and isolation by distance. Ploidy levels were more differentiated in the northern regions than in the South. The haplotype network was shallow and included one tetraploid‐only, star‐shaped cluster of haplotypes that were particularly successful colonizers. Post‐glacial migration of diploid S. gigantea occurred mainly northwards east of the Appalachian Mountains, and to a lesser degree also southward. Our data suggest that tetraploids have formed several times in North America. Haplotype number and diversity were lower in European populations than in the native range, and we found evidence that four haplotypes were introduced to Europe from two source areas, New England and the Southern Appalachian Mountains.
Analysis of structure and function of the giant protein Pf332 in Plasmodium falciparum
Authors: Hodder Anthony N. , Maier Alexander G. , Rug Melanie , Brown Monica , Hommel Mirja , Pantic Ivan , Puig‐de‐Morales‐Marinkovic Marina , Smith Brian , Triglia Tony , Beeson James , Cowman Alan F.
Published: November 2008

Virulence of Plasmodium falciparum, the most lethal parasitic disease in humans, results in part from adhesiveness and increased rigidity of infected erythrocytes. Pf332 is trafficked to the parasite‐infected erythrocyte via Maurer's clefts, structures for protein sorting and export in the host erythrocyte. This protein has a domain similar to the Duffy‐binding‐like (DBL) domain, which functions by binding to receptors for adherence and invasion. To address structure of the Pf332 DBL domain, we expressed this region, and validated its fold on the basis of the disulphide bond pattern, which conformed to the generic pattern for DBL domains. The modelled structure for Pf332 DBL had differences compared with the erythrocyte‐binding region of the αDBL domain of Plasmodium knowlesi Duffy‐binding protein (Pkα‐DBL). We addressed the function of Pf332 by constructing parasites that either lack expression of the protein or express an altered form. We found no evidence that Pf332 is involved in cytoadhesion or merozoite invasion. Truncation of Pf332 had a significant effect on deformability of the P. falciparum‐infected erythrocyte, while loss of the full protein deletion did not. Our data suggest that Pf332 may contribute to the overall deformability of the P. falciparum‐infected erythrocyte by anchoring and scaffolding.
Repression of galP, the galactose transporter in Escherichia coli, requires the specific regulator of N‐acetylglucosamine metabolism
Authors: El Qaidi Samir , Allemand Frédéric , Oberto Jacques , Plumbridge Jacqueline
Published: November 2008

Soupene et al. [J. Bacteriol. (2003) 185 5611–5626] made the unexpected observation that the presence of a mutation, in the gene for the N‐acetylglucosamine repressor, nagC, increased the growth rate of Escherichia coli MG1655 on galactose, an unrelated sugar. We have found that NagC, binds to a single, high‐affinity site overlapping the promoter of galP (galactose permease) gene and that expression of galP is repressed by a combination of NagC, GalR and GalS. In addition to the previously identified galOE operator, other gal operators further upstream are required for full repression. GalS has a specific role, as it binds with higher affinity to one of the upstream operators but its effect in vivo is only observed in the presence of GalR. Regulation of galP by three specific repressors, NagC, GalR and GalS is unusual in that it involves multiple, specific regulators from two different areas of metabolism. This novel regulation seems to be particular for E. coli and its nearest neighbour, Shigella. Other bacteria with galP orthologues, although retaining the metK‐galP gene order, do not have the NagC site. Although quantitative effects were strain specific, nagC mutations increased the growth rate on galactose of all E. coli strains tested.
DNA polymerase switching: effects on spontaneous mutagenesis inEscherichia coli
Authors: Curti Elena , McDonald John P. , Mead Samantha , Woodgate Roger
Published: November 2008

Escherichia colipossesses five known DNA polymerases (pols). Pol III holoenzyme is the cell's main replicase, while pol I is responsible for the maturation of Okazaki fragments and filling gaps generated during nucleotide excision repair. Pols II, IV and V are significantly upregulated as part of the cell's global SOS response to DNA damage and under these conditions, may alter the fidelity of DNA replication by potentially interfering with the ability of pols I and III to complete their cellular functions. To test this hypothesis, we determined the spectrum ofrpoBmutations arising in an isogenic set ofmutLstrains differentially expressing the chromosomally encoded pols. Interestingly, mutagenic hot spots inrpoBwere identified that are susceptible to the actions of pols I–V. For example, in arecA730 lexA(Def)mutLbackground most transversions were dependent upon pols IV and V. In contrast, transitions were largely dependent upon pol I and to a lesser extent, pol III. Furthermore, the extent of pol I‐dependent mutagenesis at one particular site was modulated by pols II and IV. Our observations suggest that there is considerable interplay among all fiveE. colipolymerases that either reduces or enhances the mutagenic load on theE. colichromosome.
Purification of low‐abundance Arabidopsis plasma‐membrane protein complexes and identification of candidate components
Authors: Qi Yiping , Katagiri Fumiaki
Published: November 2008

Purification of low‐abundance plasma‐membrane (PM) protein complexes is a challenging task. We devised a tandem affinity purification tag termed the HPB tag, which contains the biotin carboxyl carrier protein domain (BCCD) of Arabidopsis 3‐methylcrotonal CoA carboxylase. The BCCD is biotinylated in vivo, and the tagged protein can be captured by streptavidin beads. All five C‐terminally tagged Arabidopsis proteins tested, including four PM proteins, were functional and biotinylated with high efficiency in Arabidopsis. Transgenic Arabidopsis plants expressing an HPB‐tagged protein, RPS2::HPB, were used to develop a method to purify protein complexes containing the HPB‐tagged protein. RPS2 is a membrane‐associated disease resistance protein of low abundance. The purification method involves microsomal fractionation, chemical cross‐linking, solubilization, and one‐step affinity purification using magnetic streptavidin beads, followed by protein identification using LC‐MS/MS. We identified RIN4, a known RPS2 interactor, as well as other potential components of the RPS2 complex(es). Thus, the HPB tag method is suitable for the purification of low‐abundance PM protein complexes.
VH1/BRL2 receptor‐like kinase interacts with vascular‐specific adaptor proteins VIT and VIK to influence leaf venation
Authors: Ceserani Teresa , Trofka Anna , Gandotra Neeru , Nelson Timothy
Published: November 2008

VH1/BRL2 is a receptor‐like kinase of the BRI1 family with a role in vascular development. In developing Arabidopsis leaves it is expressed first in ground cells and then becomes restricted to provascular and procambial cells as venation forms. We isolated proteins interacting with the activated (phosphorylated) cytoplasmic domain of VH1/BRL2, and found that most belong to three processes: proteasome activity, vesicle traffic and intracellular signal transduction. Two adaptor proteins are included that we named VIT [VH1‐interacting tetratricopeptide repeat (TPR)‐containing protein] and VIK (VH1‐interacting kinase), which are co‐expressed in the same cells as VH1/BRL2 at two distinct time points in vein differentiation. Mutation of either adaptor or of VH1 results in vein pattern defects and in alterations in response to auxin and brassinosteroids. We propose that these two adaptors facilitate the diversification and amplification of a ligand signal perceived by VH1/BRL2 in multiple downstream pathways affecting venation.
Generalized pustulosis induced by adalimumab in a patient with rheumatoid arthritis – a therapeutic challenge
Authors: Kucharekova Martina , Winnepenninckx Véronique , Frank Jorge , Poblete‐Gutiérrez Pamela
Published: November 2008

Tumor necrosis factor‐alpha (TNF‐α) inhibitors such as adalimumab are increasingly used in the treatment of chronic inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. In Europe, this group of drugs also has been approved for therapy of moderate to severe psoriasis recently. With increased application of adalimumab, the possible adverse effects occurring in the course of treatment steadily gained more attention. Among these, infection and localized skin eruptions are the most common. Usually, the cutaneous symptoms rapidly resolve after discontinuation of the drug. Here, however, we report on a woman with rheumatoid arthritis who developed a therapy‐refractory, generalized pustular rash during treatment with adalimumab. After different unsuccessful therapeutic attempts, only a combined treatment with prednisone, methotrexate, and cyclosporinee eventually led to marked improvement. To the best of our knowledge, this is the first report on a generalized, therapy‐resistant pustulosis as an adverse effect of adalimumab.
Superficial thrombophlebitis of the venous dorsal arch of the foot and deep venous thrombosis after foam sclerotherapy
Authors: Shadid Nadia , Frank Jorge , Sommer Anja
Published: November 2008

Four days after foamsclerotherapy of an incompetent great saphenous vein of the left lower leg a 49‐year‐old woman developed a superficial thrombophlebitis of the venous dorsal arch. In the course of follow‐up repeated color duplex sonography initially did not show involvement of the deep venous system and, hence, she was treated with non‐steroidal anti‐inflammatory drugs and compression hosiery. However, six weeks after foam treatment we diagnosed a deep venous thrombosis (DVT) of the popliteal vein and started an oral anticoagulant therapy. Although rarely observed, DVT is among the most serious complications of foamsclerotherapy Therefore, we suggest that the occurrence of a superficial thrombophlebitis that is not located in close vicinity of the vein treated should be an indication for regular follow‐up examinations to prevent missing the occurrence of disease progression and a possible involvement of the deep venous system.
Eruption of lymphocyte recovery or autologous graft‐versus‐host disease?
Authors: Nellen Ruud G. L. , Van Marion Arienne M. W. , Frank Jorge , Poblete‐Gutiérrez Pamela , Steijlen Peter M.
Published: November 2008

Maculopapular exanthemas have a particular high incidence among patients treated with autologous hematopoietic stem cell transplantation (HSCT). In most cases, a viral or drug induced origin is easily identified. However, the transplantation itself may also induce similar skin changes. These exanthemas are known under various names, such as autologous graft‐versus‐host disease (GVHD), engraftment syndrome (ES) or eruption of lymphocyte recovery (ELR). Given the clinical and histopathological similarities of these disorders, it can prove difficult to establish a diagnosis. Here, we describe a patient who developed a maculopapular exanthema after autologous stem cell transplantation for multiple myeloma, diagnosed as autologous GVHD. We also briefly review the current knowledge of the pathogenesis of autologous GVHD, ES, and ELR. Based on these data we would like to suggest that the latter two do not reflect own disease entities but rather different presentations of autologous GVHD.
Hyperkeratosis lenticularis perstans (Flegel's disease) – successful treatment with topical corticosteroids
Authors: Sterneberg‐Vos Heleen , Van Marion Arienne M. W. , Frank Jorge , Poblete‐Gutierrez Pamela
Published: November 2008

Flegel's disease, also known as hyperkeratosis lenticularis perstans, is a rare skin disease characterized by small, red‐brown, hyperkeratotic, papules that are usually located on the lower extremities. The diagnosis is based on the clinical appearance in association with the typical histologic features of orthohyperkeratosis and a subepidermal band‐like infiltrate. Treatment is difficult and rarely fully effective. We report on a woman with Flegel's disease who responded to a topical corticosteroid therapy with betamethasone dipropionate.
Lymphedema in Prader–Willi syndrome
Authors: Heitink Martijn V. , Sinnema Margje , Van Steensel Maurice A. M. , Schrander‐Stumpel Connie T. R. M. , Frank Jorge , Curfs Leopold M. G.
Published: November 2008

A 20‐year‐old woman with Prader–Willi syndrome presented with heaviness and swelling in the lower legs and feet, which had developed after a fall. Lymphoscintigraphy showed a disturbed lymphatic drainage pattern in both lower extremities. Based on the clinical findings and the results of lymphoscintigraphic examination we made the diagnosis of lymphedema. The patient was successfully treated with manual lymphatic drainage in combination with multilayer compressive bandaging. After edema reduction, elastic compressive stockings were fit. To the best of our knowledge, this is the first report on primary lymphedema in a patient with Prader–Willi syndrome, an association that is probably often missed.
PRAVASTATIN ATTENUATES INTERFERON‐γ ACTION VIA MODULATION OF STAT1 TO PREVENT AORTIC ATHEROSCLEROSIS IN APOLIPOPROTEIN E‐KNOCKOUT MICE
Authors: Zhou Xiao‐Xu , Gao Ping‐Jin , Sun Bao‐Gui
Published: November 2008

The beneficial effects of pravastatin, beyond that of lowering cholesterol in atherosclerosis, include reducing the action of interferon (IFN)‐γ. Interferon‐γ activates the signal transducer and activator of transcription 1 (STAT1), but it is unclear whether the inhibitory effect of pravastatin in atherosclerosis is via modulation of the IFN‐γ/STAT1 pathway. Thus, the aim of the present study was to determine whether the action of pravastatin in preventing aortic atherosclerosis by attenuation of IFN‐γ action is dependent on STAT1.

Male apolipoprotein E‐knockout (apoE−/–) mice were fed a diet containing 1.25% cholesterol (w/w). Mice were divided into two groups, one of which was supplemented with pravastatin (80 mg/kg per day). Male C57BL/6J mice were fed a normal diet and served as the control group (n = 12 per group).

Atherosclerotic lesions in the aortic root were assessed by staining sections haematoxylin and eosin. Serum concentrations of IFN‐γ and IFN‐γ mRNA expression in the thoracoabdominal aorta were determined by ELISA and real‐time quantitative polymerase chain reaction methods, respectively. Expression of phosphorylated STAT1 (pSTAT1), interferon regulating factor (IRF)‐1 and suppressors of cytokine signalling 1 (SOCS1) was determined in the thoracoabdominal aorta using Western blot analysis.

After 8 weeks, pravastatin treatment significantly prevented the formation of atherosclerotic lesions (P < 0.05) and reduced serum IFN‐γ concentrations (P < 0.05) and levels of IFN‐γ mRNA within the aorta (P < 0.01). Pravastatin significantly decreased the expressions of pSTAT1 and IRF‐1 within the aorta and significantly increased expression of SOCS1.

These results suggest that the actions of pravastatin in attenuating the action of IFN‐γ and subsequently preventing aortic atherosclerosis may depend, at least in part, on modulation of STAT1 activity. This providing us with a new therapeutic approach and a clearer insight into the clinical benefits of pravastatin.
WHAT'S WHERE AND WHY AT A VASCULAR MYOENDOTHELIAL MICRODOMAIN SIGNALLING COMPLEX
Authors: Sandow Shaun L , Haddock Rebecca E , Hill Caryl E , Chadha Preet S , Kerr Paul M , Welsh Donald G , Plane Frances
Published: November 2008

Modulation of vascular cell calcium is critical for the control of vascular tone, blood flow and pressure.

Specialized microdomain signalling sites associated with calcium modulation are present in vascular smooth muscle cells, where spatially localized channels and calcium store receptors interact functionally. Anatomical studies suggest that such sites are also present in endothelial cells.

The characteristics of these sites near heterocellular myoendothelial gap junctions (MEGJs) are described, focusing on rat mesenteric artery. The MEGJs enable current and small molecule transfer to coordinate arterial function and are thus critical for endothelium‐derived hyperpolarization, regulation of smooth muscle cell diameter in response to contractile stimuli and vasomotor conduction over distance.

Although MEGJs occur on endothelial cell projections within internal elastic lamina (IEL) holes, not all IEL holes have MEGJ‐related projections (approximately 0–50% of such holes have MEGJ‐related projections, with variations occurring within and between vessels, species, strains and disease).

In rat mesenteric, saphenous and caudal cerebellar artery and hamster cheek pouch arteriole, but not rat middle cerebral artery or cremaster arteriole, intermediate conductance calcium‐activated potassium channels (IKCa) localize to endothelial cell projections.

Rat mesenteric artery MEGJ connexins and IKCaare in close spatial association with endothelial cell inositol 1,4,5‐trisphosphate receptors and endoplasmic reticulum.

Data suggest a relationship between spatially associated endothelial cell ion channels and calcium stores in modulation of calcium release and action. Differences in spatial relationships between ion channels and calcium stores in different vessels reflect heterogeneity in vasomotor function, representing a selective target for the control of endothelial and vascular function.
MELATONIN REDUCES BLOOD PRESSURE IN RATS WITH STRESS‐INDUCED HYPERTENSION VIA GABAA RECEPTORS
Authors: Li Hua‐Li , Kang Yu‐Ming , Yu Lei , Xu Hai‐Yan , Zhao Hua
Published: November 2008

Several groups have reported that melatonin produces a significant decrease in blood pressure in mammals and that pinealectomy in rats causes hypertension. The purpose of the present study was to investigate the effects of melatonin and bicuculline methiodide on the blood pressure of rats, both in the developing and fully developed stage of stress‐induced hypertension (SIH).

Rats with SIH were generated by mild electric foot shocks for 15 days, after which tail arterial systolic pressure and plasma angiotensin (Ang) II levels were measured. The effects of melatonin injections (i.p. or i.c.v.) on mean arterial pressure (MAP) in rats with SIH were also determined.

Pretreatment with 1 mg/kg, i.p., melatonin significantly diminished the elevated tail arterial systolic pressure and plasma AngII levels caused by 15 days stress. The suppressive effects of melatonin were blocked by i.p. injection of 1 mg/kg bicuculline methiodide, an antagonist of the GABAA receptor.

Intraperitoneal (0.2, 0.5 and 1 mg/kg) or i.c.v. (0.15 and 1.5 µg/3 µL) injection of melatonin produced a dose‐dependent lowering of MAP in rats with SIH. The antihypertensive response induced by melatonin was blocked by injection of both 1 mg/kg, i.p., and 1.5 × 106 µg/3 µL, i.c.v., bicuculline methiodide.

In conclusion, melatonin not only prevents increases in blood pressure during the developing stage of SIH, but can also reduce the blood pressure of rats that have already developed SIH. The antihypertensive effect of melatonin may be mediated by GABAA receptors through inhibition of plasma AngII levels.
HYPERTONICITY INCREASES RABBIT ATRIUM AND PULMONARY VEIN ARRHYTHMOGENESIS: A POTENTIAL CONTRIBUTOR TO THE GENESIS OF ATRIAL FIBRILLATION
Authors: Lee Shih‐Huang , Chen Yao‐Chang , Cheng Chen‐Chuan , Higa Satoshi , Chen Yi‐Jen , Chen Shih‐Ann
Published: November 2008

Pulmonary veins are the most important focus for the initiation of atrial fibrillation. Diabetes mellitus may be associated with hypertonicity and increased occurrence of atrial fibrillation.

The purpose of the present study was to investigate whether hypertonicity alters the electrophysiological characteristics of pulmonary veins and atria to enhance the genesis of atrial fibrillation.

A whole‐cell patch‐clamp technique was used to investigate action potentials and ionic currents in rabbit isolated single pulmonary vein and atrial cardiomyocytes during immersion in isotonic and hypertonic (1.2× normal osmolality) solutions.

Hypertonicity increased the spontaneous beating rates of pulmonary vein cardiomyocytes from 2.3 ± 0.3 to 3.4 ± 0.3 Hz (n = 11;P < 0.001). Hypertonicity prolonged action potential duration to a greater extent in atrial cardiomyocytes than in pulmonary vein cardiomyocytes. Compared with atrial cardiomyocytes, hypertonicity increased the transient inward currents and Na+/Ca2+exchange currents to a greater extent in pulmonary vein cardiomyocytes, but decreased the delayed rectified potassium currents to a lesser extent.

Hypertonicity plays an important role in the electrical activity of pulmonary vein and atrial cardiomyocytes, which may have a potential role in the pathophysiology of atrial fibrillation.
Temporal changes in the periphytic algal communities in a drowned tropical forest reservoir in Malaysia: Lake Kenyir
Authors: Rouf AJM A. , Ambak M. A. , Shamsudin Lokman , Phang Siew‐Moi , Ho Sinn C.
Published: November 2008

Periphytic algal assemblages, comprising bacillariophytes, cyanophytes and chlorophytes of standing dead trees in Lake Kenyir, a tropical drowned forest reservoir, were studied during 1995. A total of 317 algal taxa were identified in this study. The monthly floral mean species richness and cell count data demonstrated significant temporal differences between the months, in one‐way anova (P < 0.05). Both redundancy analysis and cluster analysis on monthly blue‐green abundance and diatom assemblages exhibited conspicuous groupings among the months, with underpinning seasonal differences. The responses were not similar, however, between the upstream and downstream ends of the lake. The grouping or clustering of months can be generalized as: (i) November, December and January as the monsoonal months; (ii) February, March, April and May as the transitional months; and (iii) June to October as the dry months. Based on stepwise multiple regression with forward selection, alkalinity and dissolved oxygen concentration were significant environmental predictors at the downstream dam sampling site, and reactive silica, electrical conductivity, Secchi depth transparency and sunshine hours were significant predicators at the upstream riverine sampling site, based on Monte Carlo tests. Being a ploymictic, mesotrophic lake, the limnology and temporal changes for Lake Kenyir appears to be complex and driven by monsoons, as evidenced from the temporal changes in its periphytic algae communities, particularly the diatom assemblages. The downstream sampling site (site 1) at the dam, in the main basin and deeper zone of the lake, the seasonal amplitude was likely complex because of thermocline formation and stratification processes. In contrast, the upstream sampling site in the Petang River (site 2) exhibited a clearer distinction between the dry and monsoon months, based on its cyanophyte and diatom floral assemblages. These study results are pertinent for lake management, especially for developing biomonitoring programmes or lake productivity studies, as well as for climate change studies, within the context of tropical lake ecology.
Assessment of lake–groundwater interactions and anthropogenic stresses, using numerical groundwater flow model, for a Rift lake catchment in central Ethiopia
Authors: Ayenew Tenalem , Tilahun Nardos
Published: November 2008

A steady‐state groundwater flow model (MODFLOW) was used to study lake and groundwater interactions in a complex rift volcanic catchment. It also was used to assess the effects of water pumping from wells, and of variable recharge rates associated with climate and lake level changes, on the dynamics of the volcanic aquifers surrounding Lake Awassa. The model simulations were made after first developing a reasonable conceptual model, on the basis of conventional hydrogeological mapping, pumping test and hydrometeorological data analyses, and from ancillary information obtained from hydrochemical and isotope techniques. The model results indicated that the lakes and Rift aquifers are fed by large groundwater inputs that originate in the highlands. The lakes and rivers have important roles in recharging the aquifers in some locations. Lake Awassa receives a major groundwater inflow from its southern and eastern shorelines, while substantial water leakage from the lake occurs along the northern shoreline. The annual groundwater outflow from the catchment is estimated to 52.5 × 106 m3. Scenario analyses revealed that increasing the current pumping rate from wells by fourfold will substantially reduce the groundwater level substantially, although the regional flow pattern would remain the same. There appears to be no immediate danger to the Rift aquatic environment from the current water pumping rate. Drying the small Lake Shalo and associated swamps, however, will cause a large change in the water balance of the larger Lake Awassa. Slight changes in groundwater recharge can cause large differences in groundwater levels for most of the Rift caldera floor far from the lake shores. This study provides a reasonable foundation for developing detailed transient predictive models, which can then readily be used as a decision support tool for development and implementation of sustainable water resources practices.
Genetic variations in the endangered aquatic plant Nymphoides coreana (Menyanthaceae) in south‐western Japan
Authors: SHIBAYAMA YUKI , KADONO YASURO
Published: November 2008

We surveyed allozyme variations among ten Nymphoides coreana populations in southwestern Japan. The percentage of polymorphic loci, the mean number of alleles per locus, and the effective number of alleles per locus varied little among populations. The observed heterozygosity and expected heterozygosity were low. The proportion of gene diversity of the species within populations (Hs) was also low. These indices all indicate that genetic diversity was low within the populations. The inbreeding coefficient within a population, Fis, was significantly larger than expected in each local population. A comparison between Hs and the proportional gene diversity of the species among populations (Dst) showed that almost all variations occurred among populations. Large genetic differentiation was also supported by the high value of gene diversity between populations relative to the combined populations (Gst). Nymphoides coreana is considered to be a selfing species, and genetic variations among the populations were shown to be distinct.
Meiotic behavior and pollen viability of wild populations of the neotropical species Vriesea gigantea (Bromeliaceae)
Authors: PALMA‐SILVA CLARISSE , PAGGI GECELE MATOS , FELICETTI RICARDO AUGUSTO , FERRAZ RENATO , KALTCHUK‐SANTOS ELIANE , BERED FERNANDA , BODANESE‐ZANETTINI MARIA HELENA
Published: November 2008

Plant fertility can influence many aspects of population ecology and evolution. The quantity and quality of pollen produced by a plant is an important component of reproductive success. Plant fertility was analyzed by assessing: chromosome number, meiotic behavior and pollen viability of seven native populations of Vriesea gigantea. All plants presented 2n = 50 chromosomes. Most of the pollen mother cells showed a regular meiotic behavior with 25 bivalents and regular chromosome segregation. In accordance, high pollen viability (84–98%) was recorded for all investigated populations. These results indicated that plants from all populations analyzed are fertile. Despite the overall high pollen viability, significant differences were detected among populations. The population of Praia do Araçá showed a reduced percentage of pollen viability, although meiosis was quite regular. Reduction in pollen viability could have an important effect on plants fertility and, consequently, on fitness of this population.
Demographic genetics of American beech (Fagus grandifolia Ehrh.) IV. Development of genetic variability and gene flow during succession in a coastal plain forest in Maryland
Authors: KITAMURA KEIKO , TAKASU HIDEKI , HAGIWARA SHINSUKE , HOMMA KOHSUKE , O'NEILL JAY , WHIGHAM DENNIS F. , KAWANO SHOICHI
Published: November 2008

Genetic recovery of an American beech (Fagus grandifolia) population in deciduous forests that were once pastures was studied using 16 allozyme loci from 410 individuals in a 600 m × 600 m study plot in Maryland, USA. We also examined the spatio‐temporal genetic structure of the American beech population at a regional scale. Overall genetic diversity of mature trees was measured by estimating average heterozygosity (H = 0.156). Rare alleles were observed in five loci, Lap, 6Pdgh3, Pgi, Adh1 and Got3. Mature individuals were divided into three size classes based on d.b.h. The genetic component of each size class was compared and it was revealed that several alleles (Pgm‐a, 6Pgdh3‐a and Lap‐b) were shared only in specific size classes. The spatial distribution of the genotypes demonstrated a conspicuous localization in three loci (Aco, Adh1 and Idh). Spatial autocorrelation analyses were carried out among the mature trees for a 20 m interval, and were positive for 0–120 m and negative for >180 m. Distrograms indicated that a unique genetic localization occurs among mature individuals. Seven hundred and seventy‐five seedlings in the 10 m × 120 m transect were analyzed to measure gene flow via seed and/or pollen. We obtained a genetic neighborhood area of 1.17 ha and an effective population size of 32.4. The temporal and spatial modes of genetic recovery of the population are discussed in the context of conservation biology.
Muscarinic control of the excitability of hindlimb motoneurons in chronic spinal‐transected salamanders
Authors: Chevallier Stéphanie , Nagy Frédéric , Cabelguen Jean‐Marie
Published: November 2008

The excitability of spinal motoneurons (MNs) is regulated by acetylcholine via the activation of muscarinic receptors. The objective of the present study was to determine whether this cholinergic modulation of MN excitability is altered following a chronic spinal cord transection. Juvenile salamanders (Pleurodeles waltlii) were spinally transected at the mid‐trunk level, and patch‐clamp recordings from hindlimb MNs in spinal cord slices were performed 9–30 days after transection, with and without bath application of muscarine (20 μm). Our results showed that the input–output relationship was larger in MNs recorded 2 weeks after spinal transection than in MNs recorded 3–4 weeks after spinal transection. They further revealed that muscarine increased both the gain of MNs and the proportion of MNs that could exhibit plateau potentials and afterdischarges, whereas it decreased the amplitude of the medium afterhypolarizing potential. Moreover, muscarine had no effect on the hyperpolarization‐activated cation current (Ih), whereas it increased the inward rectifying K+ current (IKir) in MNs recorded ≥ 2 weeks after spinal transection. We conclude that following chronic spinal cord injury, the muscarinic modulation of some intrinsic properties of MNs previously reported in acute spinal‐transected animals [S. Chevallier et al. (2006)The Journal of Physiology, 570, 525–540] was preserved, whereas that of other intrinsic properties of MNs was suppressed, either transiently (IKir) or definitively (Ih). These alterations in muscarinic modulation of MN excitability may contribute to the spontaneous recovery of locomotion displayed in long‐term chronic spinal‐transected salamanders.
Role of spinal 5‐HT2 receptor subtypes in quipazine‐induced hindlimb movements after a low‐thoracic spinal cord transection
Authors: Ung Roth‐V. , Landry Eric S. , Rouleau Pascal , Lapointe Nicolas P. , Rouillard Claude , Guertin Pierre A.
Published: November 2008

A role of serotonin receptors (5‐HTRs) in spinal rhythmogenesis has been proposed several years ago based mainly upon data showing that bath‐applied 5‐HT could elicit locomotor‐like rhythms in in vitro isolated spinal cord preparations. Such a role was partially confirmed in vivo after revealing that systemically administered 5‐HTR2 agonists, such as quipazine, could induce some locomotor‐like movements (LM) in completely spinal cord‐transected (Tx) rodents. However, given the limited binding selectivity of currently available 5‐HTR2 agonists, it has remained difficult to determine clearly if one receptor subtype is specifically associated with LM induction. In situ hybridization, data using tissues from L1–L2 spinal cord segments, where critical locomotor network elements have been identified in mice, revealed greater 5‐HTR2A mRNA levels in low‐thoracic Tx than non‐Tx animals. This expression level remained elevated for several days, specifically in the lateral intermediate zone, where peak values were detected at 1 week post‐Tx and returned to normal at 3 weeks post‐Tx. Behavioral and kinematic analyses revealed quipazine‐induced LM in 1‐week Tx mice either non‐pretreated or pretreated with selective 5‐HTR2B and/or 5‐HTR2C antagonists. In contrast, LM completely failed to be induced by quipazine in animals pretreated with selective 5‐HTR2A antagonists. Altogether, these results provide strong evidence suggesting that 5‐HTR2A are specifically associated with spinal locomotor network activation and LM generation induced by quipazine in Tx animals. These findings may contribute to design drug treatments aimed at promoting locomotor function recovery in chronic spinal cord‐injured patients.
Temporal filtering by prefrontal neurons in duration discrimination
Authors: Oshio Ken‐ichi , Chiba Atsushi , Inase Masahiko
Published: November 2008

Neural imaging studies have revealed that the prefrontal cortex (PFC) participates in time perception. However, actual functional roles remain unclear. We trained two monkeys to perform a duration‐discrimination task, in which two visual cues were presented consecutively for different durations ranging from 0.2 to 2.0 s. The subjects were required to choose the longer cue. We recorded single‐neuron activity from the PFC while the subjects were performing the task. Responsive neurons for the first cue period were extracted and classified through a cluster analysis of firing rate curves. The neuronal activity was categorized as phasic, ramping and sustained patterns. Among them, the phasic activity was the most prevailing. Peak time of the phasic activity was broadly distributed about 0.8 s after cue onset, leading to a natural assumption that the phasic activity was related to cognitive processes. The phasic activity with constant delay after cue onset might function to filter current cue duration with the peak time. The broad distribution of the peak time would indicate that various filtering durations had been prepared for estimating C1 duration. The most frequent peak time was close to the time separating cue durations into long and short. The activity with this peak time might have had a role of filtering in attempted duration discrimination. Our results suggest that the PFC contributes to duration discrimination with temporal filtering in the cue period.
Visual mismatch negativity for changes in orientation – a sensory memory‐dependent response
Authors: Astikainen Piia , Lillstrang Elina , Ruusuvirta Timo
Published: November 2008

It remains unclear whether the mismatch negativity of event‐related potentials (ERPs) in vision resembles its auditory counterpart in terms of memory relatedness. We recorded ERPs to visual bars in adult humans engaged in an auditory task. In one condition, a bar (‘standard’) repeated at 400‐ or 1100‐ms non‐stimulated intervals was rarely (P = 0.1) replaced by another bar of a different orientation (‘deviant’). In the other condition (400‐ms intervals), the occurrences of the standards were replaced by 10 (P = 0.1 each) bars of different orientations, including that of the deviant (‘control‐deviant’). Deviants shifted ERPs towards negative polarity relative to standards in occipital electrodes and towards positive polarity in frontal electrodes at 185–205 ms post‐stimulus but only when 400‐ms non‐stimulated intervals were applied. Furthermore, the shift existed even relative to ERPs to control‐deviants. The findings suggest that, as in audition, vision supports the detection of voluntarily unattended changes per se within the constraints of sensory memory. The findings also pave the way for the future exploration of both intact and impaired memory‐based visual processing and memory capacity.
Standardized surgery for colonic cancer: complete mesocolic excision and central ligation – technical notes and outcome
Authors: Hohenberger W. , Weber K. , Matzel K. , Papadopoulos T. , Merkel S.
Published: November 2008

Objective  Total mesorectal excision (TME) as proposed by R.J. Heald more than 20 years ago, is nowadays accepted worldwide for optimal rectal cancer surgery. This technique is focused on an intact package of the tumour and its main lymphatic drainage.

This concept can be translated into colon cancer surgery, as the mesorectum is only part of the mesenteric planes which cover the colon and its lymphatic drainage like envelopes. According to the concept of TME for rectal cancer, we perform a concept of complete mesocolic excision (CME) for colonic cancer. This technique aims at the separation of the mesocolic from the parietal plane and true central ligation of the supplying arteries and draining veins right at their roots.

Method  Prospectively obtained data from 1329 consecutive patients of our department with RO‐resection of colon cancer between 1978 and 2002 were analysed. Patient data of three subdivided time periods were compared.

Results  By consequent application of the procedure of CME, we were able to reduce local 5‐year recurrence rates in colon cancer from 6.5% in the period from 1978 to 1984 to 3.6% in 1995 to 2002. In the same period, the cancer related 5‐year survival rates in patients resected for cure increased from 82.1% to 89.1%.

Conclusion  The technique of CME in colon cancer surgery aims at a specimen with intact layers and a maximum of lymphnode harvest. This is translated into lower local recurrence rates and better overall survival.
The involvement of calpains in opacification induced by Ca2+‐overload in ovine lens culture
Authors: Lee Hannah Y. Y. , Morton James D. , Sanderson Julie , Bickerstaffe Roy , Robertson Lucinda J. G.
Published: November 2008

Objective  To investigate biochemical changes accompanying Ca2+‐induced lens opacification and the possible role of calpain activation in opacification within an ovine lens culture system.

Methods  Sheep lenses were cultured in minimal media. Lens opacification was induced by exposure to the Ca2+ ionophore, ionomycin, and graded by digital image analysis. Cell viability was estimated by the release of lactate dehydrogenase into the culture medium. Opaque lenses were fixed and stained for a microscopic view of the lens structural changes. Ionic changes in the lens were measured by atomic absorption spectroscopy. Calpain activation was determined by zymography on casein gels and proteolysis was investigated by SDS–polyacrylamide gel electrophoresis (SDS–PAGE), two‐dimensional gel electrophoresis (2DE) and Western blotting. The calpain inhibitor, SJA6017, was used to investigate the involvement of calpains in lens opacification.

Results  Treatment of cultured ovine lenses with ionomycin increased total lens Ca2+ concentration and caused the cortical region of the lens to become opaque. Addition of the Ca2+ chelator, EGTA, inhibited the ionomycin‐induced changes. Progress of opacification correlated with the death of lens cells and lens swelling in differentiating fiber cells. Autolysis of calpain 2, following ionomycin treatment, suggested activation of this protease. 2DE revealed that the ionomycin did not result in substantial proteolysis of the crystallins. However, Western blotting revealed significant breakdown of the cytoskeletal proteins, spectrin and vimentin. The pattern of the breakdown products was consistent with calpain proteolytic activity. SJA6017 retarded the cortical opacity induced by Ca2+‐overload in the ovine lens.

Conclusion  The ovine lens with Ca2+‐induced opacification by ionomycin is associated with calpain activation and the subsequent proteolysis of cytoskeletal proteins. These events could be initial factors contributing to cell death and the loss of lens transparency which occurs in this ovine model of cataractogenesis. The ovine model supports the hypothesis that cytoskeletal proteins and Ca2+ homeostasis play an important role in maintaining lens transparency.
A case of conjunctival melanoma in a cat
Authors: Payen G. , Estrada M. , Clerc B. , Chahory S.
Published: November 2008

Since 1985, 5 cases of feline conjunctival melanoma have been reported in the literature. Information on feline conjunctival melanoma epidemiological features, localizations, macroscopic features and histological features is limited. We are describing the clinical, histopathologic features and outcomes in a cat that presented clinically with a slow developing dark brown mass located under the upper eyelid of the left eye. Pertinent literature is reviewed; and the recognizable clinical features and treatment are discussed. The mass was surgically resected. Despite its size, the lesion was easily separated from underlying tissues, making possible a macroscopic complete resection that left intact the adjacent conjunctiva. The tumour histological examination has showed a pigmented melanoma lacking encapsulation, but presenting a clear zone delimiting the lesion. It was exclusively composed of epithelioid cells, and presented mild cellular anaplasia and weak mitotic activity. These features allowed it to be classified as a quite differentiated melanoma with few signs of potential malignancy. In accordance with these histologic features, no recurrence has been registered 34 months after surgery. Thus, a favorable outcome is now reported for two out of six cases of conjunctival melanoma in the cat. This report also confirms the predilection for this neoplasm to arise from the bulbar conjunctiva.
Evaluating off‐site environmental mitigation using choice modelling*
Authors: Kerr Geoffrey N. , Sharp Basil M.H.
Published: November 2008

Evaluation of off‐site mitigation entails comparison of utility changes between two sites. Choice modelling has been used to identify community willingness to trade‐off attributes for two different types of stream in New Zealand. Estimated utility functions are used to derive marginal rates of substitution and stream attribute part worths which can be used to design or evaluate both on‐site and off‐site mitigation policy. Latent class multinomial logit models identified classes of citizens who valued stream attributes quite differently. Significant differences in values for some attributes on different stream types imply heterogeneous mitigation ratios across environmental attributes.
A Microcomputer‐Based Method for Analysis and Design of Roof Systems Using Cold‐formed Z‐Sections
Authors: FENSKE T. E. , YENER M.
Published: November 2008

The widespread acceptance of cold‐formed structural steel members as roof purlins in conventionally engineered building has been hindered by the lack of a useful and efficient analysis and design methodology. This article outlines a microcomputer‐based design methodology for roof Zpurlins, the purpose of which is to provide such a tool. The design methodology details used in the development of the interactive microcomputer program Z‐BM are described herein, along with a general program description and a sample program execution. Z‐BM is based on the American Iron and Steel Institute specifications and considers the combined effect of the Z‐purlin and corrugated roof deck in resisting applied loads. In addition to echoing all input data, for each loading combination, Z‐BM provides a complete stress summary, the maximum allowable axial load, plus the maximum deflection and its location.
C‐Map: A High‐level Language for Engineering Analysis and Design
Authors: HA KINH H.
Published: November 2008

C‐MAP is a high level language for engineering computations. In addition to the conventional programming features, C‐MAP has over 100 functions covering a broad spectrum of numerical methods for engineering computations ranging from elementary calculus to non‐linear constrained optimization problems. These basic functions can be nested in innumerable ways that give C‐MAP great flexibility and power. C‐MAP comprises four integrated components: (i) a fullscreen text editor with multiple stacked windows for simultaneous editing of programs and output files; (ii) a simplified C‐like programming language with control structures, recursive functions, math library, and built‐in functions for advanced engineering computations including the processing of general matrix and complex expressions; (iii) an interactive expression processor; and (iv) a simple authoring system with automatic cross‐referencing of keywords. The program's versatility helps to meet the different needs of users at different stages of learning. A beginner may use only the built‐in functions for math and matrix operations to get immediate, useful results; the advanced users may write their own functions for more complex problems. This paper discusses the features of C‐MAP and its applications in teaching structural engineering
An AutoCAD Finite Element Analysis Interface
Authors: Henrikson S. H. , VanLuchene R. D.
Published: November 2008

Abstract: The popular CAD package AutoCAD has many features making it a useful tool for finite element model generation and output postprocessing. A true ‘WYSIWYG’ interface is developed and used in and environment familiar to many Civil Engineers. The format of the interface is presented. Specific considerations for AutoLISP programming within AutoCAD and compiled language programming are discussed. A 2‐D truss structure is presented to demonstrate use of the interface.
A Knowledge‐Based System for Synthesis and Design of Transmission Towers Using Blackboard Architecture
Authors: Aravind H. B. , Murlidharan T. L. , Sivakumar P. , Raman N. V.
Published: November 2008

Abstract: This paper describes the development of KASTLE—a knowledge‐based system for synthesis and design of steel lattice self‐supporting transmission towers. Using inputs such as type of tower, geographical location, the voltage the conductor has to carry and the number of circuits the tower has to support, an experienced designer arrives at an overall configuration of tower. An expert designer basically relies on heuristics to choose parameters, such as base width, tophamper width, type of bracings and sub‐bracing pattern, for the tower configuration. The final cost of the tower is sensitive to these initial decisions. Geometric modelling of the configuration is prerequisite for tower analysis. This paper reports an attempt to integrate different types of knowledge‐based systems using blackboard architecture. The knowledge system for configuration generation uses theorem proving, whereas in other knowledge‐based systems, such as modelling and design heuristics, knowledge has been represented using IF‐THEN rules. A sample synthesis and design of a 220 kV and 400 kV tangent tower is included. The system has been implemented on an IBM PC AT with MS‐DOS. Prolog, Fortran, and C languages were used.