bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity and Vulnerability in Marine Environments: an Approach to Identifying Vulnerable Marine Areas
Authors: ZACHARIAS MARK A. , GREGR EDWARD J.
Published: January 2005

Abstract:  Marine environments have suffered from a lack of quantitative methods for delineating areas that are sensitive or vulnerable to particular stresses, natural and anthropogenic. We define sensitivity as the degree to which marine features respond to stresses, which are deviations of environmental conditions beyond the expected range. Vulnerability can then be defined as the probability that a feature will be exposed to a stress to which it is sensitive. Using these definitions, we provide a quantitative methodology for identifying vulnerable marine areas based on valued ecological features, defined as biological or physical features, processes, or structures deemed by humans to have environmental, social, cultural, or economic significance. The vulnerability of the valued ecological features is a function of their sensitivity to particular stresses and their vulnerability to those stresses. We used the methodology to demonstrate how vulnerable marine areas for two groups of endangered whale species (inshore and offshore) could be identified with a predictive habitat model and acoustic stress surfaces. Acoustic stress surfaces were produced for ferry traffic, commercial shipping traffic, potential offshore oil production, and small‐boat traffic. The vulnerabilities of the two whale groups to the four stressors considered in this example were relatively similar; however, inshore species were more sensitive to on‐shelf, coastal activities such as offshore hydrocarbon production, ferry traffic, and small‐boat traffic. Our approach demonstrates how valued features can be associated with stresses and the likelihood of encountering these stresses (vulnerability) in order to identify geographic areas for management and conservation purposes. The method can be applied to any combination of valued ecological features and stressors.
Relative Importance of Reproductive Biology and Establishment Ecology for Persistence of a Rare Shrub in a Fragmented Landscape
Authors: YATES COLIN J. , LADD PHILIP G.
Published: January 2005

Abstract: 
Verticordia fimbrilepis (Turcz) ssp. fimbrilepis (Myrtaceae) is an endangered shrub that occurs in a number of populations varying in size and landscape context. We compared the importance of factors associated with its reproductive biology with that of factors influencing the regeneration niche in survival of small, isolated populations in contrasting habitat fragments. Small populations on road verges had equal or greater diversity of insect visitors to flowers, rates of pollination, and seed production compared with larger populations in conservation reserves. V. fimbrilepis seeds remained dormant in the soil for at least 30 months, and germination was stimulated by smoke. Plants were killed by fire, but mass recruitment from soil‐stored seed reserves occurred in the first and second winters following fire. Our studies showed some seedling recruitment between fires, but this was strongly related to the availability of competition‐free establishment sites. Whether this is enough to replace older plants as they die and thereby sustain stable populations is unknown and probably varies with the landscape. Environmental variation between fire episodes influenced population size. Drought increased mortality, but wetter years encouraged interfire recruitment. Most populations are declining and cannot recover without the occurrence of fire. In a fragmented agricultural landscape, fire suppression is the primary management practice. This may adversely affect rare species such as V. fimbrilepis and others with similar life histories that rely on a particular fire regime to persist. Population persistence is more likely to be related to stochastic environmental events than to factors associated with reproductive biology.
Scleredema Adultorum Associated with Hyperkeratosis
Authors: Engin Burhan , Mat Mehmet Cem , Demirkesen Cuyan , Kotogyan Agop , Ozdogan Huri
Published: January 2005

Abstract:  Scleredema adultorum is a rare skin disorder reported to occur usually following streptococcal infections. It has characteristic clinical and histopathologic findings; however, associated hyperkeratosis is not known. We report a 6‐year‐old girl with scleredema adultorum and hyperkeratosis. The patient's disease had a benign course. To our knowledge, this patient is the first reported with scleredema adultorum associated with hyperkeratosis.
Congenital Erosive and Vesicular Dermatosis Healing with Reticulated Supple Scarring
Authors: Metz Brandie J. , Hicks John , Levy Moise
Published: January 2005

Abstract:  Congenital erosive and vesicular dermatosis healing with reticulated supple scarring is a rare disorder of unknown etiology first reported in three patients in 1985. Nine patients have subsequently been reported, helping to further characterize this unique dermatosis. We describe another patient and further describe the histologic and electron microscopic findings of this entity. This case is unique in that histologic distinction is made between vesicular and scarred lesions.
An In Vitro Biomechanical Comparison of the Insertion Variables and Pullout Mechanical Properties of AO 6.5‐mm Standard Cancellous and 7.3‐mm Self‐Tapping, Cannulated Bone Screws in Foal Femoral Bone
Authors: Johnson Nicole L. , Galuppo Larry D. , Stover Susan M. , Taylor Ken T.
Published: January 2005

Objective—To compare screw insertion variables and pullout mechanical properties between AO 6.5‐mm cancellous and 7.3‐mm cannulated bone screws in foal femoral bone.

Study Design—A paired, in vitro mechanical study.

Sample Population—Seven pairs of femora from immature (1–7 months) foals.

Methods—The 6.5 cancellous and 7.3‐mm cannulated screws were inserted at standardized proximal and distal metaphyseal, and mid‐diaphyseal locations. Insertion torque, force, and time to drill, tap (6.5‐mm cancellous), guide wire insertion (7.3‐mm cannulated), and screw insertion were measured. Screw pullout properties (yield and failure load, displacement, and energy, and stiffness) were determined from mechanical tests. The effects of screw type and location on insertion variables and pullout properties were assessed with repeated measures ANOVA. Pairwise comparisons were examined with post hoc contrasts. Significance was set atP<.05 for all comparisons.

Results—Insertion torques for the 7.3‐mm cannulated screws were significantly greater than for the 6.5‐mm tap, but significantly lower than for the 6.5‐mm cancellous screws. Total screw insertion times were similar. Pullout properties of both screws were similar at each femoral location. The holding power of both screws was significantly greater in the mid‐diaphysis than in either metaphyseal location. Pullout failure occurred by bone shearing at the bone–screw interface in all specimens.

Conclusions—The 6.5‐mm cancellous and 7.3‐mm cannulated screws vary in insertion properties, but have similar pullout properties in the mid‐diaphysis, proximal, and distal metaphysis of foal femora. Both screw types have greater holding power at the mid‐diaphyseal location compared with metaphyseal locations. Based on overall similar holding powers of 6.5‐mm cancellous and 7.3‐mm cannulated screws, it is unlikely that increasing the screw diameter beyond 6.5 mm will provide increased holding power in foal femoral bone.

Clinical Relevance—Use of the 7.3‐mm cannulated screw should be considered for foal femoral fracture repair when greater accuracy is needed, or when bone threads for the 6.5‐mm cancellous screw have been stripped.
Red blood cell exchange transfusion in two patients with advanced erythropoietic protoporphyria
Authors: Eichbaum Quentin G. , Dzik Walter H. , Chung Raymond T. , Szczepiorkowski Zbigniew M.
Published: January 2005

BACKGROUND:  Erythropoietic protoporphyria (EPP) is a rare, autosomal dominant genetic disorder caused by the decreased or absent activity of ferrochelatase, the final enzyme in the heme biosynthetic pathway. This enzyme defect in peripheral blood progenitor cells leads to the accumulation of protoporphyrin deposits in multiple tissues. Plasmapheresis has been previously reported as an adjunctive therapy for patients with advanced hepatic EPP. Because the concentration of protoporphyrins is severalfold higher inside the red blood cell (RBC) compared to plasma, it was hypothesized that RBC exchange therapy might absorb excess protoporphyrins from the plasma and serve as an effective therapy to reduce protoporphyrin load in patients with advanced hepatic EPP. The effectiveness of RBC exchange plus hematin versus plasmapheresis plus hematin in two patients with advanced hepatic EPP is reported.

STUDY DESIGN AND METHODS:  Two patients with advanced hepatic EPP were treated with RBC exchange and plasmapheresis in the setting of recurrent disease in the graft (Patient 1) or preparation for liver transplantation (Patient 2). In vitro studies were performed to test transport of protoporphyrins from patients’ plasma to normal RBCs.

RESULTS:  Compared with plasmapheresis, RBC exchange was more effective, for the duration of the therapy, in reducing blood levels of protoporphyrins. Liver function tests, however, showed only a modest improvement during therapy. In vitro extracellular protoporphyrin were rapidly adsorbed into normal RBCs.

CONCLUSION:  Neither RBC exchange nor plasmapheresis prevented progressive hepatic deterioration in advanced hepatic EPP despite a significant decrease in protoporphyrin levels.
STAR: a novel high‐prevalence antigen in the Scianna blood group system
Authors: Hue‐Roye Kim , Chaudhuri Asok , Velliquette Randall W. , Fetics Susan , Thomas Rebecca , Balk Mary , Wagner Franz F. , Flegel William A. , Reid Marion E.
Published: January 2005

BACKGROUND:  More than 20 years ago, a proband was described whose red blood cells (RBCs) typed Sc:1,−2,3. His serum sample contained an immunoglobulin G alloantibody that reacted with all RBCs tested except his own, his brother’s, and those with the Sc:−1,−2 phenotype. Cloning of the SC gene allowed determination of the molecular basis associated with this novel high‐prevalence antigen.

STUDY DESIGN AND METHODS:  Samples from frozen storage were obtained from the proband, his serologically matched brother, and 15 serologically mismatched family members. DNA was extracted, and amplified products from all 11 SC (ERMAP) exons and their flanking regions of the proband were sequenced.

RESULTS:  A single‐nucleotide mutation was detected (139G>A) in Exon 3 that is predicted to encode a change of Amino Acid 47 from glutamic acid to lysine. The sequence analyses on samples from family members were as expected.

CONCLUSIONS:  The absence of the high‐prevalence antigen STAR detected by the proband's antibody is likely associated with lysine at Position 47 of the Sc glycoprotein. This amino acid change is located on the extracellular portion of HERMAP, 10 residues upstream from the polymorphism associated with Sc1 and Sc2 (Gly57Arg). STAR expands the Sc blood group system to five antigens and has been assigned the ISBT Number 013005 (SC5).
Prevalence and Management of Inappropriate Detection and Therapies in Patients with First‐Generation Biventricular Pacemaker‐Defibrillators
Authors: CHUGH AMAN , SCHARF CHRISTOPH , HALL BURR , CHEUNG PETER , GOOD ERIC , HORWOOD LAURA , ORAL HAKAN , PELOSI FRANK , MORADY FRED
Published: January 2005

Background: Tachycardia detection in first‐generation biventricular pacemaker‐implantable cardioverter defibrillators (BiV ICD) occurs through both the right ventricular (RV) and left ventricular (LV) leads, creating the potential for inappropriate detection and therapies. Little is known regarding the prevalence and management of patients with BiV ICDs and inappropriate detection.

Methods and Results: A transvenous, first‐generation BiV ICD was implanted in 77 consecutive patients (age 61 ± 11 years) for drug‐refractory heart failure. The mean New York Heart Association class, QRS duration, and ejection fraction were 3.1 ± 0.4, 168 ± 24 ms, and 0.19 ± 0.07, respectively. Among the 77 patients, 17 (22%) experienced inappropriate detection at a mean of 154 ± 140 days after implantation. Fifteen of the 17 patients (88%) experienced inappropriate ICD therapy. In 16 of the 17 (94%) patients, the cause of inappropriate detection was double counting during sinus (8) or atrial rhythm (3), and nonsustained ventricular tachycardia (5). Despite reprogramming of the ICD, 9 patients (53%) required an additional procedure because of inappropriate therapies, including an upgrade to a dedicated BiV ICD (5), revision of the LV lead (2), ablation of the atrioventricular junction (1), and repeat defibrillation threshold testing (2).

Conclusions: Inappropriate detection in patients with a first‐generation BiV ICD is common and often results in inappropriate ICD therapy. The most common mechanism of inappropriate detection is double counting that often creates the need for additional procedures. Although devices in which tachycardia detection occurs only through the RV lead now are available, close follow‐up of the many patients who received a first‐generation BiV ICD is necessary.
Increased persistent Na+ current and its effect on excitability in motoneurones cultured from mutant SOD1 mice
Authors: Kuo J. J. , Siddique T. , Fu R. , Heckman C. J.
Published: January 2005

Mutations in the enzyme superoxide dismutase 1 (SOD1) initiate a progressive motoneurone degeneration in amyotrophic lateral sclerosis (ALS). Transgenic mice overexpressing this mutation develop a similar progressive motoneurone degeneration. In spinal motoneurones cultured from presymptomatic mice expressing the glycine to alanine mutation at base pair 93 (G93A) SOD1 mutation, a marked increase in the persistent component of the Na+ current was observed, without changes in passive properties. This increase only enhanced neuronal excitability in high input conductance cells, as low input conductance cells exhibited a compensatory outward shift in the current remaining after Na+ blockade. High input conductance motoneurones tend to be large, so these results may explain the tendency of large motoneurones to degenerate first in ALS. Riluzole, at the therapeutic concentration used to treat ALS, decreased neuronal excitability and persistent Na+ current in G93A motoneurones to levels observed in the control motoneurones. Aberrations in the intrinsic electrical properties may be among the first symptoms to emerge in SOD1‐linked ALS.
Skeletal muscle pumpversusrespiratory muscle pump: modulation of venous return from the locomotor limb in humans
Authors: Miller Jordan D. , Pegelow David F. , Jacques Anthony J. , Dempsey Jerome A.
Published: January 2005

The vast majority of quantitative data examining the effects of breathing on venous return have been derived from anaesthetized or reduced animal preparations, making an extrapolation to an upright exercising human problematic due to the lack of a hydrostatic column and an absence of muscular contraction. Thus, this study is the first to quantitatively examine the effects of different breathing mechanics on venous return from the locomotor limbs both at rest and during calf contraction exercise in the semirecumbent human. When subjects inspired using predominantly their ribcage/accessory inspiratory muscles at rest (change in gastric pressure(ΔPGA) = <2 cmH2O, change in oesophageal pressure(ΔPES) =∼−6 cmH2O; inspiratory time/total breath time (TI/TTOT) = 0.5), a slight facilitation of femoral venous return was observed during inspiration (65% of all flow occurred during inspiration), with a slight reduction in femoral venous return during the ensuing expiratory phase of the breath. However, when subjects inspired using a predominantly diaphragmatic breath at rest(ΔPGA= > 5 cmH2O, ΔPES=∼−6 cmH2O;TI/TTOT= 0.5), femoral venous return was markedly impeded (net retrograde flow of 11%) and significantly lower than that observed during ribcage breathing conditions (P< 0.01). During the ensuing expiratory phase of a diaphragmatic breath, there was a large resurgence of femoral venous blood flow. The pattern of modulation during ribcage and diaphragmatic breathing persisted during both mild (peak calf force = 7 kg) and moderate (peak calf force = 11 kg) levels of calf contraction. Despite the significant within‐breath modulation of femoral venous return by breathing, net blood flow in the steady state was not altered by the breathing pattern followed by the subjects. Though popliteal blood flow appeared to be modulated by respiration at rest, this pattern was absent during mild calf contraction where popliteal outflow was phasic with the concentric phase of calf contraction. We conclude that respiratory muscle pressure production is the predominant factor modulating venous return from the locomotor limb both at rest and during calf contraction even when the veins of the lower limb are distended due to the presence of a physiologic hydrostatic column.
Subunit‐specific gating controls rat NR1/NR2A and NR1/NR2B NMDA channel kinetics and synaptic signalling profiles
Authors: Erreger Kevin , Dravid Shashank M. , Banke Tue G. , Wyllie David J. A. , Traynelis Stephen F.
Published: January 2005

NR2A and NR2B are the predominant NR2 NMDA receptor subunits expressed in cortex and hippocampus. The relative expression level of NR2A and NR2B is regulated developmentally and these two subunits have been suggested to play distinct roles in long‐term synaptic plasticity. We have used patch‐clamp recording of recombinant NMDA receptors expressed in HEK293 cells to characterize the activation properties of both NR1/NR2A and NR1/NR2B receptors. Recordings from outside‐out patches that contain a single active channel show that NR2A‐containing receptors have a higher probability of opening at least once in response to a brief synaptic‐like pulse of glutamate than NR2B‐containing receptors (NR2A, 0.80; NR2B, 0.56), a higher peak open probability (NR2A, 0.50; NR2B, 0.12), and a higher open probability within an activation (NR2A, 0.67; NR2B, 0.37). Analysis of the sequence of single‐channel open and closed intervals shows that both NR2A‐ and NR2B‐containing receptors undergo multiple conformational changes prior to opening of the channel, with at least one of these steps being faster for NR2A than NR2B. These distinct properties produce profoundly different temporal signalling profiles for NR2A‐ and NR2B‐containing receptors. Simulations of synaptic responses demonstrate that at low frequencies typically used to induce long‐term depression (LTD; 1 Hz), NR1/NR2B makes a larger contribution to total charge transfer and therefore calcium influx than NR1/NR2A. However, under high‐frequency tetanic stimulation (100 Hz; > 100 ms) typically used to induce long‐term potentiation (LTP), the charge transfer mediated by NR1/NR2A considerably exceeds that of NR1/NR2B.
Na+–K+ pump stimulation restores carbacholine‐induced loss of excitability and contractility in rat skeletal muscle
Authors: Macdonald W. A. , Nielsen O. B. , Clausen T.
Published: January 2005

Intense exercise results in increases in intracellular Na+ and extracellular K+ concentrations, leading to depolarization and a loss of muscle excitability and contractility. Here, we use carbacholine to chronically activate the nicotinic acetylcholine (nACh) receptors to mimic the changes in membrane permeability, chemical Na+ and K+ gradients and membrane potential observed during intense exercise. Intact rat soleus muscles were mounted on force transducers and stimulated electrically to evoke short tetani at regular intervals. Carbacholine produced a 2.6‐fold increase in Na+ influx that was tetrodotoxin (TTX) insensitive, but abolished by tubocurarine, resulting in a significant 36% increase in intracellular Na+, and 8% decrease in intracellular K+ content. The mid region, near the motor end plate, had much larger alterations than the more distal regions of the muscle, and showed a larger membrane depolarization from −73 ± 1 to −60 ± 1 mV compared with −64 ± 1 mV. Carbacholine (10−4m) significantly reduced tetanic force to 31 ± 3% of controls, which underwent significant recovery upon application of Na+–K+ pump stimulators: salbutamol (10−5m), adrenaline (10−5m) and calcitonin gene‐related peptide (CGRP; 10−7m). The force recovery with salbutamol was accompanied by a recovery of intracellular Na+ and K+ contents, and a small but significant 4–5 mV recovery of membrane potential. Similar results were obtained using succinylcholine (10−4m), indicating that Na+–K+ pump stimulation may prevent or restore succinylcholine‐induced hyperkalaemia. The stimulation of the Na+–K+ pump allows muscle to partially recover contractility by regaining excitability through electrogenically driven repolarization of the muscle membrane.
The Genome of the Basidiomycetous Yeast and Human Pathogen
Cryptococcus neoformans
Authors: Loftus Brendan J. , Fung Eula , Roncaglia Paola , Rowley Don , Amedeo Paolo , Bruno Dan , Vamathevan Jessica , Miranda Molly , Anderson Iain J. , Fraser James A. , Allen Jonathan E. , Bosdet Ian E. , Brent Michael R. , Chiu Readman , Doering Tamara L. , Donlin Maureen J. , D'Souza Cletus A. , Fox Deborah S. , Grinberg Viktoriya , Fu Jianmin , Fukushima Marilyn , Haas Brian J. , Huang James C. , Janbon Guilhem , Jones Steven J. M. , Koo Hean L. , Krzywinski Martin I. , Kwon-Chung June K. , Lengeler Klaus B. , Maiti Rama , Marra Marco A. , Marra Robert E. , Mathewson Carrie A. , Mitchell Thomas G. , Pertea Mihaela , Riggs Florenta R. , Salzberg Steven L. , Schein Jacqueline E. , Shvartsbeyn Alla , Shin Heesun , Shumway Martin , Specht Charles A. , Suh Bernard B. , Tenney Aaron , Utterback Terry R. , Wickes Brian L. , Wortman Jennifer R. , Wye Natasja H. , Kronstad James W. , Lodge Jennifer K. , Heitman Joseph , Davis Ronald W. , Fraser Claire M. , Hyman Richard W.
Published: January 2005

Cryptococcus neoformans
is a basidiomycetous yeast ubiquitous in the environment, a model for fungal pathogenesis, and an opportunistic human pathogen of global importance. We have sequenced its â¼20-megabase genome, which contains â¼6500 intron-rich gene structures and encodes a transcriptome abundant in alternatively spliced and antisense messages. The genome is rich in transposons, many of which cluster at candidate centromeric regions. The presence of these transposons may drive karyotype instability and phenotypic variation.
C. neoformans
encodes unique genes that may contribute to its unusual virulence properties, and comparison of two phenotypically distinct strains reveals variation in gene content in addition to sequence polymorphisms between the genomes.
Manual and Automated Instrumentation for Identification ofEnterobacteriaceaeand Other Aerobic Gram-Negative Bacilli
Authors: O'Hara Caroline M.
Published: January 2005

Identification of gram-negative bacilli, both enteric and nonenteric, by conventional methods is not realistic for clinical microbiology laboratories performing routine cultures in today's world. The use of commercial kits, either manual or automated, to identify these organisms is a common practice. The advent of rapid or “spot” testing has eliminated the need for some commonly isolated organisms to be identified with the systems approach. Commercially available systems provide more in-depth identification to the species level as well as detect new and unusual strains. The answers obtained from these systems may not always be correct and must be interpreted with caution. The patient demographics, laboratory workload and work flow, and technologist's skill levels should dictate the system of choice. Cost considerations introduce another variable into the equation affecting choice. Each system has its own strengths and weaknesses, and each laboratory must decide on the level of sophistication that fulfills its particular needs.
AspergillusInfections in Transplant Recipients
Authors: Singh Nina , Paterson David L.
Published: January 2005

Aspergillusinfections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.
DNA Methylation in Lysogens of Pathogenic
Burkholderia
spp. Requires Prophage Induction and Is Restricted to Excised Phage DNA
Authors: Smith M. J. , Jeddeloh J. A.
Published: January 2005

Burkholderia mallei
-specific phage ΦE125 encodes DNA methyltransferases in both the lysogenic and replication modules within its genome. Characterization of DNA methylation in recombinant systems, specifically in ΦE125 lysogenic strains of
B. mallei
and
Burkholderia thailandensis
, revealed that, upon induction, cytosine methylation was targeted specifically to the phage episome but not the phage provirus or the host chromosome.
Expression Profiling of Virulence and Pathogenicity Genes ofXanthomonas axonopodispv. citri
Authors: Astua-Monge Gustavo , Freitas-Astua Juliana , Bacocina Gisele , Roncoletta Juliana , Carvalho Sérgio A. , Machado Marcos A.
Published: January 2005

DNA macroarrays of 279 genes ofXanthomonas axonopodispv. citri potentially associated with pathogenicity and virulence were used to compare the transcriptional alterations of this bacterium in response to two synthetic media. Data analysis indicated that 31 genes were up-regulated by synthetic medium XVM2, while only 7 genes were repressed. The results suggest that XVM2 could be used as an in vitro system to identify candidate genes involved in pathogenesis ofX.axonopodispv. citri.
Substrate Requirements for Regulated Intramembrane Proteolysis ofBacillus subtilisPro-σK
Authors: Prince Heather , Zhou Ruanbao , Kroos Lee
Published: January 2005

During sporulation ofBacillus subtilis, pro-σKis activated by regulated intramembrane proteolysis (RIP) in response to a signal from the forespore. RIP of pro-σKremoves its prosequence (amino acids 1 to 20), releasing σKfrom the outer forespore membrane into the mother cell cytoplasm, in a reaction catalyzed by SpoIVFB, a metalloprotease in the S2P family of intramembrane-cleaving proteases. The requirements for pro-σKto serve as a substrate for RIP were investigated by producing C-terminally truncated pro-σKfused at different points to the green fluorescent protein (GFP) or hexahistidine in sporulatingB. subtilisor inEscherichia coliengineered to coexpress SpoIVFB. Nearly half of pro-σK(amino acids 1 to 117), including part of sigma factor region 2.4, was required for RIP of pro-σK-GFP chimeras in sporulatingB. subtilis. Likewise, pro-σK-hexahistidine chimeras demonstrated that the N-terminal 117 amino acids of pro-σKare sufficient for RIP, although the N-terminal 126 amino acids, which includes all of region 2.4, allowed much better accumulation of the chimeric protein in sporulatingB. subtilisand more efficient processing by SpoIVFB inE. coli. In contrast to the requirements for RIP, a much smaller N-terminal segment (amino acids 1 to 27) was sufficient for membrane localization of a pro-σK-GFP chimera. Addition or deletion of five amino acids near the N terminus allowed accurate processing of pro-σK, ruling out a mechanism in which SpoIVFB measures the distance from the N terminus to the cleavage site. A charge reversal at position 13 (substituting glutamate for lysine) reduced accumulation of pro-σKand prevented detectable RIP by SpoIVFB. These results elucidate substrate requirements for RIP of pro-σKby SpoIVFB and may have implications for substrate recognition by other S2P family members.
Ochrobactrum tritici strain 5bvl1 — characterization of a Cr(VI)-resistant and Cr(VI)-reducing strain
Authors: Branco Rita , Alpoim M Carmen , Morais Paula V
Published: January 2005

Bacterial strain 5bvl1, isolated from a chromium-contaminated wastewater treatment plant and identified as Ochrobactrum tritici, was resistant to a broad range of antibiotics, to Cr(VI), Ni(II), Co(II), Cd(II), and Zn(II), and was able to grow in the presence of 5% NaCl and within the pH range 4–10. Characterization showed that strain 5bvl1 could be considered a halotolerant and alkalitolerant microorganism resistant to high concentrations of Cr(VI). This strain was able to grow aerobically in up to 10 mmol·L–1 Cr(VI). Cr(VI) resistance was independent of sulphate concentration. Under aerobic conditions strain 5bvl1 was also able to reduce high Cr(VI) concentrations (up to 1.7 mmol·L–1). Increasing concentrations of Cr(VI) in the medium lowered the growth rate of strain 5bv11 but the reduction in growth rate could not be directly correlated with the amount of Cr(VI) reduced. Unlike the type strain, which was only able to reduce Cr(VI), strain 5bvl1 was resistant to Cr(VI) and able to reduce it. Moreover, in strain 5bvl1, the rate and extent of Cr(VI)-reduction were higher than in the other strains of the genus Ochrobactrum. Ochrobactrum strain 5bvl1 resists high Cr(VI) concentrations and has a high Cr(VI)-reducing ability, making it a valuable tool in bioremediation.Key words: Ochrobactrum, Cr(VI) resistance, Cr(VI)-reduction, heavy metal, bioremediation.
Role of MetR and PurR in the activation ofglyAby CsgD inEscherichia coliK-12
Authors: Chirwa Neema T , Herrington Muriel B
Published: January 2005

The csgD gene of Escherichia coli is required for the expression of curli fibres, surface fibres that are important for biofilm formation and infection. Previously, we demonstrated that expression of CsgD from a multicopy plasmid increased expression of the glyA gene, which codes for serine hydroxymethyltransferase. We show here that this activation requires the participation of both known regulatory proteins, MetR and PurR. The adjacent divergently transcribed gene hmp was weakly induced by CsgD, but its induction did not require MetR or PurR. The effect of CsgD on the expression of several pur and met genes was also tested.Key words: curli, regulation, serine hydroxymethyltransferase, Hmp, one-carbon, dihydrofolate reductase, MetR, PurR.
Sporocarps ofPisolithus albusas an ecological niche for fluorescent pseudomonads involved inAcacia mangiumWild –Pisolithus albusectomycorrhizal symbiosis
Authors: Duponnois Robin , Lesueur Didier
Published: January 2005

Fresh sporocarps and root and soil samples were collected under a monospecific forest plantation of Acacia mangium in Dagana in Northern Senegal and checked for the presence of fluorescent pseudomonads. No bacteria were detected except from sporocarps collected with adhering soil and hyphal strands. Pisolithus sporocarps were dried at 30 °C for 2 weeks, ground, passed through a 2-mm sieve and mixed together. This dry sporocarp powder (DSP) was used to inoculate and form mycorrhizas on A. mangium seedlings in a glasshouse experiment. After 3 months culture, plant growth was increased in the DSP treatment but no ectomycorrhizas were present on the A. mangium root systems; however fluorescent pseudomonads were recorded in the cultural soil. The stimulatory effects on the plant growth were maintained for 6 months. However, fluorescent pseudomonads were no longer detected and 35% of the short roots were ectomycorrhizal. Some of the fluorescent pseudomonad isolates detected after 3 months stimulated the radial fungal growth in axenic conditions. These observations suggest that these bacteria are closely associated with the Pisolithus fructifications and could interact with the ectomycorrhizal symbiosis establishment.Key words: ectomycorrhizal symbiosis, fluorescent pseudomonads, Pisolithus, Acacia.
Characterization, regulation, and phylogenetic analyses of thePenicillium griseoroseumnitrate reductase gene and its use as selection marker for homologous transformation
Authors: Pereira Jorge Fernando , Queiroz Marisa Vieira de , Lopes Francis Júlio Fagundes , Rocha Rodrigo Barros , Daboussi Marie-Josée , Araújo Elza Fernandes de
Published: January 2005

Penicillium griseoroseum has been studied because of its efficient pectinases production. In this work, the Penicillium griseoroseum nitrate reductase gene was characterized, transcriptionaly analyzed in different nitrogen sources, and used to create a phylogenetic tree and to develop a homologous transformation system. The regulatory region contained consensus signals involved in nitrogen metabolism and the structural region was possibly interrupted by 6 introns coding for a deduced protein with 864 amino acids. RT–PCR analysis revealed high amounts of niaD transcript in the presence of nitrate. Transcription was repressed by ammonium, urea, and glutamine showing an efficient turnover of the niaD mRNA. Phylogenetics analysis showed distinct groups clearly separated in accordance with the classical taxonomy. A mutant with a 122-bp deletion was used in homologous transformation experiments and showed a transformation frequency of 14 transformants/µg DNA. All analyzed transformants showed that both single- and double-crossover recombination occurred at the niaD locus. The establishment of this homologous transformation system is an essential step for the improvement of pectinase production in Penicillium griseoroseum.Key words: nitrate reductase, nitrogen metabolism, Penicillium griseoroseum, phylogenetic analysis, homologous transformation.
Monitoring of grizzly bear population trends and demography using DNA mark–recapture methods in the Owikeno Lake area of British Columbia
Authors: Boulanger J , Himmer S , Swan C
Published: January 2005

We used DNA sampling and mark–recapture modeling to estimate population trend(s), population size, and the demographic response of a coastal British Columbia grizzly bear population (Ursus arctos L., 1758) to low salmon escapement levels from 1998 to 2002. We contrasted the demography of three sampling areas in response to temporal and spatial variation in salmon availability. Population trend (λ) estimates suggested that salmon availability was too low in the first 2 years of the study to sustain grizzly bear populations. One of the sampling areas exhibited higher levels of salmon availability in later years of the study, leading to increased rates of addition. Apparent survival rates increased in all areas potentially as a result of increased salmon availability. Joint interpretation of λ and superpopulation estimates allowed for the assessment of whether salmon availability levels were high enough to sustain current population sizes of grizzly bears on salmon streams. This study illustrates how joint modeling of separate sampling areas can be used to assess spatial variation in population demography and population trends, as well as increase precision of estimates for individual sampling areas. It also illustrates how DNA mark–recapture can be used as a methodology to explore the effects of changes in environmental conditions on population demography and population trend of grizzly bears or of other wildlife species.
Number, seasonal movements, and residency characteristics of river dolphins in an Amazonian floodplain lake system
Authors: Martin A R , da Silva V M.F
Published: January 2005

The size and structure of a community of Amazon river dolphins or botos, Inia geoffrensis (de Blainville, 1817), was investigated using boat surveys and long-term observations of recognisable animals. Year-round, some 260 botos occurred in or near the 225-km2 Mamirauá várzea floodplain lake system, of which half were permanent residents by our definition. Seasonal variation in water levels influenced distribution between habitats but not the overall number of botos. Ninety percent of marked botos encountered within the lake system were permanent residents. There appeared to be a cline in site fidelity between those that always live in or near the system and those that visit at intervals of years. We estimated that 270 botos were "significant users" of the lake system (i.e., occurred within it for sufficient periods in a year to be observed at least once) and that many others visited for short periods. Individuals moved many tens to hundreds of kilometres along the rivers, but there was no broad-scale seasonal migration. The boto population of the central Amazon, at least, may be structured on the basis of floodplain lake systems, with extensive animal movement between systems. We estimate that 13 000 botos occur in the 11 240 km2 Mamirauá Sustainable Development Reserve, which covers an estimated 11%–18% of várzea habitat in Brazil.
Size-dependent foraging of larval Atlantic cod (Gadus morhua)
Authors: Puvanendran Velmurugu , Salies Karine , Laurel Benjamin , Brown Joseph A
Published: January 2005

Most marine fish larvae are thought to be gape-limited predators, and the presence of suitably sized prey at the appropriate time in the foraging environment is a key factor for their growth and survival. Two experiments were carried out: in experiment 1, we investigated feeding of Atlantic cod (Gadus morhua L., 1758) larvae from 5 to 35 days post hatch on prey of three different sizes: two different-sized strains of rotifers, small rotifers (SR) and large rotifers (LR), and Artemia Leach, 1819 nauplii (AN), or an equal mixture of the three types of prey (MIX). In experiment 2, cod larvae were fed SR, LR, or a combination of SR and LR (MIX-R) at concentrations of 1500 and 4000 prey·L–1from 4 to 20 days post hatch. Feeding incidence, number of prey in the gut, mouth gape, and prey selection were measured. In experiment 1, feeding incidence was initially higher in the SR treatment, while larvae failed to start feeding in either the LR or the AN treatment at 5 dph. Larvae in the LR treatment started feeding at 8 dph, and feeding incidence was comparable to that in the SR treatment, but the total number of prey eaten was higher in the SR than in the LR treatment until 20 dph. Larvae did not start feeding on AN until 26 dph, although they attacked them from 5 dph. In the MIX-R treatment in experiment 2, larvae fed selectively on LR at 4000 prey·L–1, whereas no selection was observed at 1500 prey·L–1. Our results suggest that cod larvae are gape-limited predators and the concentration of prey affects prey selection.
The function of sound production by Atlantic cod as inferred from patterns of variation in drumming muscle mass
Authors: Rowe Sherrylynn , Hutchings Jeffrey A
Published: January 2005

We quantified variation in the mass of drumming muscles (the sound-producing musculature) among individual Atlantic cod (Gadus morhua L., 1758) for comparison with other evidence on the role of sexual selection in the evolution of sound production by this species. Based on 913 cod sampled from the Western Scotian Shelf in 2001–2002, we found that males had drumming muscles that were larger than those of females and that increased in mass prior to spawning and declined thereafter. Drumming muscle mass was highly variable, particularly among males, and generally more variable than other morphological traits (somatic mass and body length). This pattern of drumming muscle variation is consistent with the hypothesis that drumming muscles are influenced by sexual selection and suggests that sound production by males during the spawning season has fitness benefits, perhaps through a role in mate competition. Drumming muscle mass of spawning males was also positively associated with body size, condition, and fertilization potential, suggesting that sound production may be an indicator of the size of the signaler and may reveal information about individual quality. In conjunction with previous studies of sound production by Atlantic cod, our study underscores the potential importance of sound production to cod spawning behaviour.
Foraging ecology of Great Black-backed Gulls during brood-rearing in the Bay of Fundy, New Brunswick
Authors: Gilliland S G , Ankney C D , Hicklin P W
Published: January 2005

We studied nesting ecology of Great Black-backed Gulls (Larus marinus L., 1758) in the Bay of Fundy, New Brunswick, in 1988 and 1989. We documented diet, feeding rate, and meal size for chicks from hatching to fledging. In 1989, colonies consisted of about 350 nests on five islands. Brood size declined with chick age, and by the end of the first week of the nestling period, 11%, 22%, 31%, and 36% of nests consisted of broods of 0, 1, 2, and 3 chicks, respectively. Average meals size increased and feeding frequency declined slightly with chick age. We estimated that 619.6 kg (dry mass) of food was fed to chicks during the nestling period in 1989. The composition of the chicks' diet changed with age and was most varied early in the nestling period, when they were fed relatively equal proportions of major food types. Overall, Atlantic herring (Clupea harengus L., 1758) was the most important prey item and contributed 63% of the energy consumed by chicks during the nestling period. Northern krill (Meganyctiphanes norvegica (M. Sars, 1857); 11.9%), lumpfish (Cyclopterus lumpus L., 1758; 10.4%), and waste (fisheries and domestic; 4.7%) were also important foods. Gull chicks and Common Eider (Somateria mollissima (L., 1758)) ducklings made up 1.9% and 0.8%, respectively, of the chicks' energy budget. We conclude that the primary factor effecting productivity of the Great Black-backed Gull was food availability, and the amount of food available varied little over the nesting period in 1989.
Effects of wastewater from an oil-sand-refining operation on survival, hematology, gill histology, and swimming of fathead minnows
Authors: Farrell A P , Kennedy C J , Kolok A
Published: January 2005

This study examined the effects of various types of wastewater produced in oil-sand-refining on the survival, hematology, gill morphology, and swimming of caged fathead minnows (Pimephales promelas Rafinesque, 1820). At the reference site, all fish survived a 28-day exposure with unchanged hematocrit, leucocrit, and gill histology. In contrast, all fish did not survive a 28-day period in any of the wastewaters tested and, in some cases, they had all died within 96 h. In addition, the hematology or gill morphology of fish that had survived shorter exposure durations was found to be significantly altered; the changes included a significant decrease in lymphocytes and significant gill cellular hyperplasia and hypertrophy. The present data suggest that water remediation will be needed before the process wastewater from oil-sand-refining can support fish populations.
Evidence of a state-dependent trade-off between energy intake and parasite avoidance in Steller's eiders
Authors: Bustnes Jan O , Galaktionov Kirill V
Published: January 2005

We examined the hypothesis that Steller's eiders, Polysticta stelleri (Pallas, 1769), in good body condition avoided nutritious and abundant prey that were intermediate hosts of acanthocephalans, while birds in poor condition accepted the long-term costs of parasitism to minimize the short-term risk of starvation. We predicted that the intensity of the acanthocephalan Polymorphus phippsi (Kostylev, 1922) should be positively related to the intake of intermediate hosts and that the intake of such prey should be negatively related to body condition. All Steller's eiders were infected (2–1142 parasites/bird). Only the intake of the amphipod Gammarus oceanicus (Segerstråle, 1947), a known intermediate host of P. phippsi, was significantly related to parasite intensity. Juvenile Steller's eiders were in poorer condition than adults and fed more on amphipods (44% vs. 9% of total biomass). On the contrary, adults preferred isopods (26% of total biomass vs. 12% for juveniles), which were less abundant than littoral amphipods but were not intermediate hosts of P. phippsi. Moreover, in juveniles there was a negative relationship between body condition and the proportion of amphipods in the diet. Hence, juveniles in poor body condition consumed potentially infected prey while adults and juveniles in good condition avoided such prey. The cost of avoiding littoral amphipods was probably a lower energy return per unit feeding effort.
Anogenital gland secretions code for sex and age in the giant panda, Ailuropoda melanoleuca
Authors: Yuan Hong , Liu Dingzhen , Sun Lixing , Wei Rongping , Zhang Guiquan , Sun Ruyong
Published: January 2005

Anogenital gland secretions play a major role in chemical communication by giant pandas, Ailuropoda melanoleuca (David, 1869). We analyzed 45 samples of anogenital gland secretions collected from 24 captive pandas (5 male adults, 6 female adults, 6 male subadults, and 7 female subadults) by gas chromatography and mass spectrometry. The secretions contained over 95 compounds. Based on 56 common compounds (relative abundances >0.1%) shared by more than three individuals, we identified steroids, long-chain fatty acids, fatty-acid esters, aldehydes, alkanes, alkenes, amines, terpenes, and furans. The chemical composition of each secretion was individual-specific. Although none of these individual compounds was age- or sex-specific, the relative abundances of several compounds differed between males and females and between adults and subadults. This result shows that information about sex and age could be coded in analog form. Information about age but not gender could also be digitally coded by the presence or absence of some of the 56 compounds, in addition to the analog coding.
COMPUTATIONAL FLUID DYNAMICS MODELLING OF ELECTRO-STRUCTURED FLOWS
Authors: BULLOUGH W. A. , KINSELLA J. R. , PEEL D. J. , URANG U. S.
Published: January 2005

The use of computational fluid dynamics (CFD) software for modelling the flow of electro-structured fluids is introduced. A non-Newtonian fluids package written specifically to model Bingham plastics is validated for several flow rates between stationary parallel plates for varying yield stresses, plate separations and lengths. The computing procedure is rationalised in terms of grid fitting of the 'plug' edge. The programme is modified to include an analytical expression which relates delectro-rheological fluid parameters. This approach is then used to predict valve flow rates from small sample, Couette viscometer produced data: its output compares with experimental results.
MOLECULAR ORIENTATION AND ELECTROHYDRODYNAMIC FLOW IN HOMOGENEOUS ER FLUIDS
Authors: IWATSUKI HIROKI , GOHKO NAOTO , KIMURA HIROSHI , MASUBUCHI YUICHI , TAKIMOTO JUN-ICHI , KOYAMA KIYOHITO
Published: January 2005

Homogeneous ER fluid is an ER fluid which consists of a homogeneous fluid only; it is neither a suspension nor a blend of immiscible liquids. Various liquid crystals are typical examples of homogeneous ER fluids. Recently, we have found that urethane-modified polypropylene glycol (UPPG) is one of the very few examples of homogeneous ER fluids which show no liquid crystalline order. In order to clarify the mechanism of the ER effect in this fluid, we have studied, in this paper, electrohydrodynamic flow under shear and electric field.
BINGHAM AND RESPONSE CHARACTERISTICS OF ER FLUIDS IN SHEAR AND FLOW MODES
Authors: LEE H. G. , CHOI S. B. , HAN S. S. , KIM J. H. , SUH M. S.
Published: January 2005

This paper presents field-dependent Bingham and response characteristics of ER fluid under shear and flow modes. Two different types of electroviscometers are designed and manufactured for the shear mode and flow mode, respectively. An ER fluid consisting of soluble chemical starches (particles) and silicon oil is made and its field-dependent yield stress is experimentally distilled at two different temperatures using the electroviscometers. Time responses of the ER fluid to step electric fields are also evaluated under two operating modes. In addition, a cylindrical ER damper, which is operated under the flow mode, is adopted and its measured damping force is compared with predicted one obtained from Bingham model of the shear and flow mode, respectively.