bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmembrane proteins are not required for early stages of nuclear envelope assembly
Authors: Ramos Corinne , Rafikova Elvira R. , Melikov Kamran , Chernomordik Leonid V.
Published: November 2006

All identified membrane fusion proteins are transmembrane proteins. In the present study, we explored the post-mitotic reassembly of the NE (nuclear envelope). The proteins that drive membrane rearrangements in NE assembly remain unknown. To determine whether transmembrane proteins are prerequisite components of this fusion machinery, we have focused on nuclear reconstitution in a cell-free system. Mixing of soluble interphase cytosolic extract and MV (membrane vesicles) from amphibian eggs with chromatin results in the formation of functional nuclei. We replaced MV and cytosol with protein-free phosphatidylcholine LS (liposomes) that were pre-incubated with interphase cytosol. While later stages of NE assembly yielding functional nucleus did not proceed without integral proteins of MV, LS-associated cytosolic proteins were sufficient to reconstitute membrane targeting to the chromatin and GTP-dependent lipid mixing. Binding involved LS-associated A-type lamin, and fusion involved Ran GTPase. Thus in contrast with post-fusion stages, fusion initiation in NE assembly, like membrane remodelling in budding and fission, does not require transmembrane proteins.
China's Pharmaceutical Revolution and Emerging Contenders
Authors: Capie Susan
Published: November 2006

The past decade has seen tremendous changes in China's economic, political and regulatory aspects, and have led to an unprecedented consolidation in the industry. These changes have fostered competitiveness among the remaining Chinese manufacturers who increasingly recognise the need to upgrade to enter into the regulated markets and also to have some balance of sales on the domestic market. This paper will examine how seven companies are dealing with the current challenges and what strategies they are implementing to become contenders in the international arena. All have tremendous potential but have inherent problems that must be overcome to emerge as pharmaceutical ‘powers’.
Prevention and reversal of cardiac hypertrophy by soluble epoxide hydrolase inhibitors
Authors: Xu Danyan , Li Ning , He Yuxia , Timofeyev Valeriy , Lu Ling , Tsai Hsing-Ju , Kim In-Hae , Tuteja Dipika , Mateo Robertino Karlo P. , Singapuri Anil , Davis Benjamin B. , Low Reginald , Hammock Bruce D. , Chiamvimonvat Nipavan
Published: November 2006

Sustained cardiac hypertrophy represents one of the most common causes leading to cardiac failure. There is emerging evidence to implicate the involvement of NF-κB in the development of cardiac hypertrophy. However, several critical questions remain unanswered. We tested the use of soluble epoxide hydrolase (sEH) inhibitors as a means to enhance the biological activities of epoxyeicosatrienoic acids (EETs) to treat cardiac hypertrophy. sEH catalyzes the conversion of EETs to form the corresponding dihydroxyeicosatrienoic acids. Previous data have suggested that EETs may inhibit the activation of NF-κB-mediated gene transcription. We directly demonstrate the beneficial effects of several potent sEH inhibitors (sEHIs) in cardiac hypertrophy. Specifically, we show that sEHIs can prevent the development of cardiac hypertrophy using a murine model of pressure-induced cardiac hypertrophy. In addition, sEHIs reverse the preestablished cardiac hypertrophy caused by chronic pressure overload. We further demonstrate that these compounds potently block the NF-κB activation in cardiac myocytes. Moreover, by using
in vivo
electrophysiologic recordings, our study shows a beneficial effect of the compounds in the prevention of cardiac arrhythmias that occur in association with cardiac hypertrophy. We conclude that the use of sEHIs to increase the level of the endogenous lipid epoxides such as EETs may represent a viable and completely unexplored avenue to reduce cardiac hypertrophy by blocking NF-κB activation.
Melatonin Protection against Lead-Induced Changes in Human Neuroblastoma Cell Cultures
Authors: Suresh Challa , Dennis Adanna O. , Heinz Josephine , Vemuri Mohan C. , Chetty C. S.
Published: November 2006

The nervous system is the primary target for low-levels of lead (Pb) exposure and the developing brain appears to be especially vulnerable to Pb neurotoxicity. Chronic low-level Pb exposure causes growth retardation and intellectual impairment. In the present study the protective effect of melatonin during exposure to low-levels of Pb in human SH-SY5Y neuroblastoma cell cultures was assessed. The cells were exposed to Pb (0.01 to 10 μM) for 48 h. Pb inhibited the proliferation of neuroblastoma cells significantly in a concentration-dependent manner. A 50% inhibition (IC50) of cell proliferation was observed at about 5 μM Pb. Pb decreased (16% to 62%) the levels of total cellular glutathione (GSH) in a concentration (0.1 to 10 μM)-dependent manner. Exposure of cells to Pb (5 μM) for 48 h resulted in an eightfold increase in caspase-3 activity and prostaglandin E2 (PGE2) level. Pretreatment with melatonin (10 μM) blocked the effects of Pb on GSH content and caspase-3 activity, and showed significant improvement in reducing the level of PGE2. The results suggest that some of the neurotoxic effects of Pb may be partly mediated by apoptosis and pretreatment with melatonin can prevent these effects. The present study asserts the neuroprotective effect of melatonin in conditions of Pb-induced toxicity in neuroblastoma cell cultures.
``Eyes Wide Shut'' — Sexuality and risk in HIV-positive youth in Sweden: A qualitative study
Authors: Christianson Monica , Lalos Ann , Westman Göran , Johansson Eva E.
Published: November 2006

Aims: This study explores the perception of sexual risk-taking behaviour in young HIV+ women and men in Sweden and their understanding of why they caught HIV. Method: In-depth interviews were conducted with 10 HIV+ women and men aged 17—24 years, 7 born in Sweden and 3 immigrants. Interviews were tape-recorded, transcribed verbatim, and analysed according to the stages of grounded theory. Results: The core category varying agency in the gendered sexual arena illustrated a spectrum of power available to these informants during sexual encounters. Two subcategories contextualized sexual practice: sociocultural blinds and from consensual to forced sex. Lack of adult supervision as a child, naïve views, being in love, alcohol and drugs, the macho ideal, and cultures of silence surrounding sexuality both individually and structurally all blinded them to the risks, making them vulnerable. Grouping narratives according to degree of consensus in sexual encounters demonstrated that sexual risks happened in a context of gendered power relations. Conclusion: This pioneering study reveals mechanisms that contribute to vulnerability and varied agency that may help in understanding why and how young people are at risk of contracting HIV. Public health strategies, which consider the role of gender and social background in the context of risky behaviours, could be developed from these findings.
Inhibition of Rho A activity causes pemphigus skin blistering
Authors: Waschke Jens , Spindler Volker , Bruggeman Paola , Zillikens Detlef , Schmidt Gudula , Drenckhahn Detlev
Published: November 2006

The autoimmune blistering skin diseases pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are mainly caused by autoantibodies against desmosomal cadherins. In this study, we provide evidence that PV–immunoglobulin G (IgG) and PF-IgG induce skin blistering by interference with Rho A signaling. In vitro, pemphigus IgG caused typical hallmarks of pemphigus pathogenesis such as epidermal blistering in human skin, cell dissociation, and loss of desmoglein 1 (Dsg 1)–mediated binding probed by laser tweezers. These changes were accompanied by interference with Rho A activation and reduction of Rho A activity. Pemphigus IgG–triggered keratinocyte dissociation and Rho A inactivation were p38 mitogen-activated protein kinase dependent. Specific activation of Rho A by cytotoxic necrotizing factor-y abolished all pemphigus-triggered effects, including keratin retraction and release of Dsg 3 from the cytoskeleton. These data demonstrate that Rho A is involved in the regulation of desmosomal adhesion, at least in part by maintaining the cytoskeletal anchorage of desmosomal proteins. This may open the possibility of pemphigus treatment with the epidermal application of Rho A agonists.
Did2 coordinates Vps4-mediated dissociation of ESCRT-III from endosomes
Authors: Nickerson Daniel P. , West Matthew , Odorizzi Greg
Published: November 2006

The sorting of transmembrane cargo proteins into the lumenal vesicles of multivesicular bodies (MVBs) depends on the recruitment of endosomal sorting complexes required for transport (ESCRTs) to the cytosolic face of endosomal membranes. The subsequent dissociation of ESCRT complexes from endosomes requires Vps4, a member of the AAA family of adenosine triphosphatases. We show that Did2 directs Vps4 activity to the dissociation of ESCRT-III but has no role in the dissociation of ESCRT-I or -II. Surprisingly, vesicle budding into the endosome lumen occurs in the absence of Did2 function even though Did2 is required for the efficient sorting of MVB cargo proteins into lumenal vesicles. This uncoupling of MVB cargo sorting and lumenal vesicle formation suggests that the Vps4-mediated dissociation of ESCRT-III is an essential step in the sorting of cargo proteins into MVB vesicles but is not a prerequisite for the budding of vesicles into the endosome lumen.
Unassisted translocation of large polypeptide domains across phospholipid bilayers
Authors: Brambillasca Silvia , Yabal Monica , Makarow Marja , Borgese Nica
Published: November 2006

Although transmembrane proteins generally require membrane-embedded machinery for integration, a few can insert spontaneously into liposomes. Previously, we established that the tail-anchored (TA) protein cytochrome b(5) (b5) can posttranslationally translocate 28 residues downstream to its transmembrane domain (TMD) across protein-free bilayers (Brambillasca, S., M. Yabal, P. Soffientini, S. Stefanovic, M. Makarow, R.S. Hegde, and N. Borgese. 2005. EMBO J. 24:2533–2542). In the present study, we investigated the limits of this unassisted translocation and report that surprisingly long (85 residues) domains of different sequence and charge placed downstream of b5's TMD can posttranslationally translocate into mammalian microsomes and liposomes at nanomolar nucleotide concentrations. Furthermore, integration of these constructs occurred in vivo in translocon-defective yeast strains. Unassisted translocation was not unique to b5 but was also observed for another TA protein (protein tyrosine phosphatase 1B) whose TMD, like the one of b5, is only moderately hydrophobic. In contrast, more hydrophobic TMDs, like synaptobrevin's, were incapable of supporting unassisted integration, possibly because of their tendency to aggregate in aqueous solution. Our data resolve long-standing discrepancies on TA protein insertion and are relevant to membrane evolution, biogenesis, and physiology.
An S6 Mutation in BK Channels Reveals β1 Subunit Effects on Intrinsic and Voltage-dependent Gating
Authors: Wang Bin , Brenner Robert
Published: November 2006

Large conductance, Ca2+- and voltage-activated K+ (BK) channels are exquisitely regulated to suit their diverse roles in a large variety of physiological processes. BK channels are composed of pore-forming α subunits and a family of tissue-specific accessory β subunits. The smooth muscle–specific β1 subunit has an essential role in regulating smooth muscle contraction and modulates BK channel steady-state open probability and gating kinetics. Effects of β1 on channel's gating energetics are not completely understood. One of the difficulties is that it has not yet been possible to measure the effects of β1 on channel's intrinsic closed-to-open transition (in the absence of voltage sensor activation and Ca2+ binding) due to the very low open probability in the presence of β1. In this study, we used a mutation of the α subunit (F315Y) that increases channel openings by greater than four orders of magnitude to directly compare channels' intrinsic open probabilities in the presence and absence of the β1 subunit. Effects of β1 on steady-state open probabilities of both wild-type α and the F315Y mutation were analyzed using the dual allosteric HA model. We found that mouse β1 has two major effects on channel's gating energetics. β1 reduces the intrinsic closed-to-open equilibrium that underlies the inhibition of BK channel opening seen in submicromolar Ca2+. Further, PO measurements at limiting slope allow us to infer that β1 shifts open channel voltage sensor activation to negative membrane potentials, which contributes to enhanced channel opening seen at micromolar Ca2+ concentrations. Using the F315Y α subunit with deletion mutants of β1, we also demonstrate that the small N- and C-terminal intracellular domains of β1 play important roles in altering channel's intrinsic opening and voltage sensor activation. In summary, these results demonstrate that β1 has distinct effects on BK channel intrinsic gating and voltage sensor activation that can be functionally uncoupled by mutations in the intracellular domains.
Paraneoplastic acrokeratosis of Bazex (Bazex's syndrome): Report of a female case associated with cholangiocarcinoma and review of the published work
Authors: KARABULUT Ayşe Anil , ŞAHİN Sedef , ŞAHİN Muzaffer , EKŞIOĞLU Meral , ÜSTÜN Hüseyin
Published: November 2006

Paraneoplastic acrokeratosis of Bazex (PAB) or Bazex's syndrome is a rare, paraneoplastic syndrome that mostly affects men over 40 years old, and generally associates with squamous cell carcinoma of the upper aerodigestive tract. We describe a 57‐year‐old woman with the characteristic features of PAB, including violaceous erythematous, scaling eruption, palmoplantar keratoderma and nail dystrophy. Further analysis revealed the underlying neoplasm to be cholangiocarcinoma. The clinical aspects of PAB and associated neoplasms are reviewed.
Primary squamous cell carcinoma of the frontal sinus
Authors: YOSHIDA Nobuyo , KANEKURA Takuro , HASHIGUCHI Takaki , NAGAYAMA Tetsuya , HAMADA Hiroshi , KANZAKI Tamotsu
Published: November 2006

We report a 74‐year‐old Japanese man with squamous cell carcinoma (SCC) originating in the frontal sinus. It presented as a cutaneous nodule on his right forehead. Magnetic resonance imaging (MRI) revealed invasion of the anterior wall of the ethmoid sinus, the frontal bone, and possibly the meninx by a frontal sinus carcinoma. Despite right fronto craniotomy with en bloc resection followed by two courses of radiation therapy and chemotherapy with 5‐fluorouracil and nedaplatin or TS‐1 he died of disease‐related causes 20 months later. Herein, we present a detailed description of this patient and a review of the published work.
Burn scars treated by pinhole method using a carbon dioxide laser
Authors: WHANG Sung Won , LEE Kyu‐yeop , CHO Sung Bin , LEE Sang Joo , KANG Jin Moon , KIM Young Koo , NAM In Hwan , CHUNG Kee Yang
Published: November 2006

Many patients with burn injuries have various complications and emotional problems due to scars. Although various modalities to improve burn scars have been attempted, such as excision of scars, skin grafts, laser abrasion and silicone product usage, the cosmetic outcomes have not been satisfactory for a large portion of patients. Herein, we describe two cases which showed satisfactory cosmetic results after treatment of burns scars with the pinhole method using a carbon dioxide (CO2) laser that allowed us to make deep, closely set holes reaching down to the upper dermis. A 20‐year‐old female patient with a scar on her neck and a 25‐year‐old female patient with a scar on her right forearm after burn injuries are presented. As early as only a few weeks after the treatment, the scars showed relaxation of contracture, reduction of wrinkles and improvement of texture and color compared to before the treatment. Treatment of burn scars with the pinhole method can be easily performed and results in dramatic improvement in scar quality with only a few side‐effects.
Calcinosis cutis of the fingertip associated with Raynaud's phenomenon
Authors: YANG Jeong Hoon , KIM Jee Woong , PARK Hyun Su , JANG Sang Jai , CHOI Jung Chul
Published: November 2006

Cutaneous calcification may be divided into four major categories: (i) dystrophic; (ii) metastatic; (iii) idiopathic; and (iv) iatrogenic. Dystrophic calcification is the most common type of calcinosis cutis and is associated with a variety of diseases. It most notably occurs in connective tissue diseases. Diffuse and limited cutaneous systemic sclerosis is an example of connective tissue diseases that frequently show calcinosis. We experienced a case of fingertip calcinosis cutis associated with Raynaud's phenomenon. The patient had no previous trauma, skin lesion or systemic connective tissue disease. We propose that calcinosis cutis of the fingertip may result from chronic ischemic injury caused by Raynaud's phenomenon.
Antinuclear antibodies giving the ‘multiple nuclear dots’ or the ‘rim‐like/membranous’ patterns: diagnostic accuracy for primary biliary cirrhosis
Authors: GRANITO A. , MURATORI P. , MURATORI L. , PAPPAS G. , CASSANI F. , WORTHINGTON J. , GUIDI M. , FERRI S. , DE MOLO C. , LENZI M. , CHAPMAN R. W. , BIANCHI F. B.
Published: November 2006

Background  Serum antinuclear antibodies giving the ‘multiple nuclear dots’ or the ‘rim‐like/membranous’ patterns are frequently detected by indirect immunofluorescence on HEp‐2 cells in patients with primary biliary cirrhosis.

Aim  To assess the accuracy of multiple nuclear dot and rim‐like/membranous antinuclear antibodies for the diagnosis of primary biliary cirrhosis.

Methods  Sera from 4371 consecutive patients referred to our laboratory were analysed under code for antinuclear antibodies testing by indirect immunofluorescence on HEp‐2 cells.

Results  Review of the clinical records of the 4371 patients allowed identification of 101 patients with antimitochondrial antibody‐positive primary biliary cirrhosis and 22 with antimitochondrial antibody‐negative variant. Multiple nuclear dot and/or rim‐like/membranous patterns were found in 59 (1.3%) of the 4371 patients: 31 antimitochondrial antibody‐positive primary biliary cirrhosis, 17 antimitochondrial antibody‐negative primary biliary cirrhosis and 11 non‐primary biliary cirrhosis. The specificity for primary biliary cirrhosis of both the antinuclear antibodies pattern was 99%. Positive predictive value and likelihood ratio for a positive test were 86% (95% CI: 72.7–94) and 221 (95% CI: 91.7–544) for multiple nuclear dot, 79% (95% CI: 62.2–90.1) and 132 (95% CI: 56.8–312.7) for rim‐like/membranous, respectively.

Conclusions  Multiple nuclear dot and rim‐like/membranous antinuclear antibodies are rare findings. Their positivity strongly suggests the diagnosis of primary biliary cirrhosis, irrespective of antimitochondrial antibody status. The high specificity for primary biliary cirrhosis makes them a useful diagnostic tool especially in antimitochondrial antibody‐negative patients.
Repeated epicutaneous exposures to ovalbumin progressively induce atopic dermatitis‐like skin lesions in mice
Authors: Wang G. , Savinko T. , Wolff H. , Dieu‐Nosjean M. C. , Kemeny L. , Homey B. , Lauerma A. I. , Alenius H.
Published: November 2006

Background
Atopic dermatitis (AD) is a chronic skin disease in which environmental factors play a great role. A widely used murine model for AD has provided a useful tool to study the disease.

Objective
The purpose of this study is to investigate kinetically the induction of this AD model and the processes involved in the development of AD due to extrinsic allergen exposures.

Methods
BALB/c mice were epicutaneously exposed to ovalbumin (OVA) for 3 weeks; each week was separated by a 2‐week resting period. Mice were killed after each exposure week. Skin biopsies and blood were obtained for histological study, RNA isolation and antibody analysis.

Results
There was a progressive and significant thickening of the epidermis and dermis in OVA‐exposed mice. Significantly increased dermal cell infiltration of eosinophils, mast cells and total inflammatory cells, including CD3 and CD4 cells, was found after each OVA exposure week. Total IgE, IgG2a and OVA‐specific IgE were significantly increased after the second and third exposure week, while OVA‐specific IgG2a was significantly induced after the third exposure week. Gradual and/or significant increases in mRNA expression of IL‐1β, TNF‐α, IL‐4, IL‐10, IL‐13, IFN‐γ and IL‐12p35 were found after each exposure week. Chemokines and their receptors involved in both T‐helper type 1 (Th1)‐ and Th2‐type cell recruitment (CCL1, CCL8, CCL11, CCL24, CXCL9, CXCL10, CCR1, CCR3, CCR5, CCR8 and CXCR3) were up‐regulated significantly at different time‐points.

Conclusion
This study provides an insight into the dynamic nature and time‐dependent transition of skin inflammation and systemic immune responses in a murine AD model induced by repeated epicutaneous exposures to OVA.
Hev b 6.01 and Hev b 5 induce pro‐inflammatory cytokines and chemokines from peripheral blood mononuclear cells in latex allergy
Authors: Lehto M. , Kotovuori A. , Palosuo K. , Varjonen E. , Lehtimäki S. , Kalkkinen N. , Palosuo T. , Reunala T. , Alenius H.
Published: November 2006

Background
Hev b 6.01 (prohevein) and Hev b 5 [acidic natural rubber latex (NRL) protein] are major IgE‐binding allergens in NRL allergy.

Objective
To examine allergen‐specific cytokine and chemokine responses in NRL‐allergic patients.

Methods
Fourteen NRL‐allergic patients and 10 healthy controls participated in the study. Hev b 6.01 and Hev b 5 were purified under non‐denaturating conditions by chromatographic methods. Specific IgE antibodies were measured by ELISA and proliferation of peripheral blood mononuclear cells (PBMC) by 3H‐thymidine incorporation assay. Allergen‐specific induction of cytokine and chemokine mRNA in PBMC was measured by real‐time PCR and protein levels by ELISA. Surface expression of chemokine receptors was analysed by flow cytometry.

Results
Twelve (86%) NRL‐allergic patients had positive skin prick test reactions and IgE antibodies against Hev b 6.01, but less than 30% responded to Hev b 5. Cell proliferation against Hev b 6.01, but not against Hev b 5, was significantly increased. Both allergens elicited significantly higher expression of pro‐inflammatory and T‐helper type 2 cytokines (TNF, IL‐12p40, IL‐13) and chemokines (CCL3, CCL4, CCL20) in the NRL‐allergic patients than in controls. Interestingly, mRNA expression of the regulatory cytokine TGF‐β1 was reduced, whereas IL‐10 expression was enhanced after allergen stimulations in patients with NRL allergy. Finally, the NRL‐allergic patients showed increased CCR4 expression on CD3+CD8− T cells and decreased CXCR3 expression on CD3+CD8+ T cells.

Conclusion
Allergen‐specific induction of cytokines and chemokines in PBMC and chemokine receptor expression on circulating T cells may contribute to the pathogenesis of NRL allergy.
Honey bee and bumblebee trypanosomatids: specificity and potential for transmission
Authors: RUIZ‐GONZÁLEZ MARIO X. , BROWN MARK J. F.
Published: November 2006

Abstract 1. Experimental studies of multihost parasite dynamics are scarce. Understanding the transmission dynamics of parasites in these systems is a key task in developing better models of parasite evolution and to make more accurate predictions of disease dynamics.

2. Bumblebee species (Bombus spp.) host the trypanosomatid parasite, Crithidia bombi. Its transmission in the field occurs through the shared use of flowers. Flowers are a perfect scenario for inter‐taxa transmission of diseases because they are used by a wide range of animals.

3. Honey bees host a poorly studied trypanosomatid, Crithidia mellificae. In this study, five questions have been experimentally addressed: (a) Can C. bombi infect honey bees? (b) Can C. mellificae infect bumblebees? (c) Can the honey bee act as a vector for C. bombi? (d) Are C. bombi cells present in honey‐bee faeces? (e) Does C. bombi have an effect on the mortality of honey bees after ingestion?

4. While both parasites were found to be specific to their hosts at the genus level, results suggest that honey bees may play a role in the epidemiology of C. bombi transmission.
Effects of habitat loss, habitat fragmentation, and isolation on the density, species richness, and distribution of ladybeetles in manipulated alfalfa landscapes
Authors: ZAVIEZO TANIA , GREZ AUDREY A. , ESTADES CRISTIÁN F. , PÉREZ ASTRID
Published: November 2006

Abstract 1. Habitat loss and fragmentation are the main causes of changes in the distribution and abundance of organisms, and are usually considered to negatively affect the abundance and species richness of organisms in a landscape. Nevertheless, habitat loss and fragmentation have often been confused, and the reported negative effects may only be the result of habitat loss alone, with habitat fragmentation having nil or even positive effects on abundance and species richness.

2. Manipulated alfalfa micro‐landscapes and coccinellids (Coleoptera: Coccinellidae) are used to test the effects habitat loss (0% or 84%), fragmentation (4 or 16 fragments), and isolation (2 or 6 m between fragments) on the density, species richness, and distribution of native and exotic species of coccinellids.

3. Generally, when considering only the individuals in the remaining fragments, habitat loss had variable effects while habitat fragmentation had a positive effect on the density of two species of coccinellids and on species richness, but did not affect two other species. Isolation usually had no effect. When individuals in the whole landscape were considered, negative effects of habitat loss became apparent for most species, but the positive effects of fragmentation remained only for one species.

4. Native and exotic species of coccinellids did not segregate in the different landscapes, and strong positive associations were found most often in landscapes with higher fragmentation and isolation.

5. The opposing effects of habitat loss and fragmentation may result in a nil global effect; therefore it is important to separate their effects when studying populations in fragmented landscapes.
Modelling the hydraulic preferences of benthic macroinvertebrates in small European streams
Authors: DOLÉDEC SYLVAIN , LAMOUROUX NICOLAS , FUCHS ULRIKE , MÉRIGOUX SYLVIE
Published: November 2006

1. Relating processes occurring at a local scale to the natural variability of ecosystems at a larger scale requires the design of predictive models both to orientate stream management and to predict the effects of larger scale disturbances such as climate changes. Our study contributes to this effort by providing detailed models of the hydraulic preferences of 151 invertebrate taxa, mostly identified at the species level. We used an extensive data set comprising 580 invertebrate samples collected using a Surber net from nine sites of second and third order streams during one, two or three surveys at each site. We used nested non‐linear mixed models to relate taxon local densities to bed shear stresses estimated from FliesswasserStammTisch hemisphere numbers.

2. An average model by taxon, i.e. independent from surveys, globally explained 25% of the density variations of taxa within surveys. A quadratic relationship existed between the average preferences and the niche breadth of taxa, indicating that taxa preferring extreme hemisphere numbers had a reduced hydraulic niche breadth. A more complete model, where taxa preferences vary across surveys, globally explained 38% of the variation of taxa densities within surveys. Variations in preferences across surveys were weak for taxa preferring extreme hemisphere numbers.

3. There was a significant taxonomic effect on preferences computed from the complete model. By contrast, season, site, average hemisphere number within a survey and average density of taxa within a survey used as covariates did not consistently explain shifts in taxon hydraulic preferences across surveys.

4. The average hydraulic preferences of taxa obtained from the extensive data set were well correlated to those obtained from two additional independent data sets collected in other regions. The consistency of taxon preferences across regions supports the use of regional preference curves for estimating the impact of river management on invertebrate communities. By contrast, the hydraulic niche breadths of taxa computed from the different data sets were not related.
Associations between anuran tadpoles and salinity in a landscape mosaic of wetlands impacted by secondary salinisation
Authors: SMITH MICHAEL J. , SCHREIBER E. SABINE G. , SCROGGIE MICHAEL P. , KOHOUT MICHELE , OUGH KEELY , POTTS JOANNE , LENNIE RUTH , TURNBULL DEREK , JIN CHANGHAO , CLANCY TIM
Published: November 2006

1. The secondary salinisation of wetlands is a global problem that poses a great threat to most freshwater biodiversity, including amphibians. We examined tadpole diversity in relation to wetland conductivity (our proxy for salinity) in wetlands in south‐eastern Australia to better understand (i) how salinity and amphibian diversity interact and (ii) the threat posed by secondary salinisation.

2. Six tadpole species were trapped in 56 wetlands that reflected a typical salinity gradient for the study region. We developed Bayesian models to examine the relationships between conductivity and both the probability of species occupancy and expected number of species with the imperfect detection probability of species accounted for in the models.

3. The probability of occupancy for all species and expected species number was negatively associated with wetland conductivity. Our results predict that conductivity should not limit tadpole presence below about 3000 μS cm−1 at 25 °C (approximately 6% seawater) in the region, but will largely exclude amphibian larvae beyond about 6000 μS cm−1 at 25 °C (approximately 12% seawater).

4. We also detected subtle among‐species differences in salinity tolerance. The results reported here show that tadpoles in the study region are likely to be negatively affected by projected future increases in salinisation.
Stream channel geomorphology influences mussel abundance in southern Appalachian streams, U.S.A.
Authors: GANGLOFF M. M. , FEMINELLA J. W.
Published: November 2006

1. Studies of North American streams have shown that hydraulic parameters and stream geomorphology can explain unionid mussel abundance at both the reach and catchment scale. However, few studies have examined applicability of hydrogeomorphic variables across broader spatial scales, such as across whole catchments, or have elucidated conditions under which spates can affect mussel populations in streams.

2. We quantified freshwater mussel abundance and species richness and their physical habitat at 24 sites in eight streams in southern Appalachian catchments in 2000 and 2001. In addition, we modelled site‐specific hydraulic parameters during summer baseflow and bankfull stages to estimate high‐ and low‐discharge conditions, respectively.

3. Mussel abundance was related to stream geomorphology, whereas richness was related to stream size. Baseflow habitat parameters explained only minor variation in abundance or richness, and both measures were highly correlated with mean current velocity or stream size. Bankfull shear stress composed a relatively low proportion of overall mussel habitat variability, but it accounted for significant variation in abundance and richness.

4. Mussel abundance was highly variable at sites subject to low‐shear stress during spates, whereas abundance always was low at sites subject to high‐shear stress. These data suggest that habitat conditions during floods, rather than those at summer baseflow, limit the abundance of mussels in Appalachian streams. These data also suggest that mussel abundance and assemblage structure may be sensitive to any changes in channel geomorphology and hydraulic conditions that might result from land use in the catchment.
Multi‐scale analysis of responses of stream macrobenthos to forestry activities and environmental context
Authors: MARTEL NICOLAS , RODRÍGUEZ MARCO A. , BÉRUBÉ PIERRE
Published: November 2006

1. Forestry activities can greatly modify the structure and function of invertebrate communities in streams, but the ability to detect effects of forestry may depend on the spatial scale considered, the choice of response metric and the environmental context. In this study, a multi‐scale, multi‐metric approach was used to compare the usefulness of proximate and larger‐scale measurements of forestry activity for understanding the impacts of forestry on stream macrobenthos.

2. Site‐specific responses of macrobenthic communities to forestry activities measured at four spatial scales (sub‐basin and 8‐, 2‐ and 0.5‐km radii upstream of study sites) were examined for 90 riffle sites distributed among 22 tributary streams (Strahler order 1–5) of the Cascapedia River basin, Quebec, Canada.

3. Multiple regression models and canonical correspondence analysis were used to relate six biological metrics (taxonomic richness, numerical density, biomass density, normalised biomass spectrum, individual body mass and community structure) to variables quantifying logging 1–19 years prior to the study and road density. Environmental predictors (variables quantifying local habitat or landscape features) were included in all analyses to statistically account for environmental context and increase the likelihood of detecting potentially subtle forestry impacts.

4. Forestry activities measured at the larger (sub‐basin and 8 km) scales were linked to decline in taxonomic richness, increase in numerical and biomass densities and shift in size structure of benthic macroinvertebrates, indicating that analyses encompassing larger areas, up to the full basin, may allow for more sensitive detection of effects than those of more limited span.

5. These responses primarily reflected marked increases in the abundance of chironomids and decline in the number of trichopteran taxa with increasing areal coverage of recent (≤2–4 years) cuts, suggesting that larger, longer‐lived and possibly more specialised taxa were more vulnerable to forestry impacts than smaller, multivoltine, generalist invertebrates. After partialling out the influence of other variables, rapid decline in richness occurred even when <1% of the basin had been clear cut in the year prior to the study.

6. Effects of forestry were detected after statistically accounting for natural environmental variability, which may have otherwise concealed those effects. The combined use of multiple biological metrics, partialling out of environmental effects and measurement of impacts at multiple spatial scales may be a broadly applicable approach for enhancing sensitivity and facilitating interpretation in studies of anthropogenic effects on macroinvertebrate communities.
The response of macroinvertebrate production to a pollution gradient in a headwater stream
Authors: WOODCOCK THOMAS S. , HURYN ALEXANDER D.
Published: November 2006

1. This study quantified patterns of macroinvertebrate secondary production and stored benthic organic matter along a gradient of pollution and habitat channelisation over a 3‐km reach of Goosefare Brook, a first‐order stream in southern Maine (U.S.A.).

2. Whole‐community invertebrate production decreased from 26.4 g ash‐free dry mass (AFDM) m−2 year−1 at the reference station to 1.1 g AFDM m−2 year−1 at stations with the greatest levels of pollution. Production decreased along the pollution gradient for most taxa, although decreases were partly offset by production increases in tolerant taxa. Biomass turnover rates (P/B) were less affected by the stresses than was production.

3. Differences in functional characteristics of the community were evident at stations with channelised habitat, but overall production declined in a linear pattern that mirrored the pollution gradient. Stored organic matter showed a decline along the gradient, but was also lower at channelised stations. Populations of taxa with documented pollution tolerance were more likely to maintain or increase production and P/B.

4. Decreasing biomass because of decreasing stored organic matter and lethal effects of pollutants resulted in shifts in the pathways of energy flow observed at stations exposed to moderate physical or chemical stress, to the loss of most taxa and an extreme (96%) decrease in production at the stations receiving the highest levels of metal pollution.

5. The shifting prominence of different taxa along a continuum of stress in Goosefare Brook shows that describing the nature of an impairment in a functional context requires consideration of chemical stressors, habitat alterations and food resources.
The effect of host Chlorella NC64A carbon : phosphorus ratio on the production of Paramecium bursaria Chlorella Virus‐1
Authors: CLASEN JESSICA L. , ELSER JAMES J.
Published: November 2006

1. We used the freshwater alga Chlorella NC64A (Division Chlorophyta) and its virus Paramecium bursaria Chlorella virus‐1 (PBCV‐1) as a model system to test for potential stoichiometric constraints on a virus–host interaction.

2. Media phosphorus concentrations were manipulated to create Chlorella NC64A host cells with low (91 ± 23) or high (453 ± 246) C : P ratio. In contrast, the C : P ratio of PBCV‐1, calculated from its biochemical composition, was 17 : 1.

3. Stoichiometric theory predicts that infection success and postinfection viral production should be depressed in high C : P cultures due to insufficient intracellular P for production of P‐rich viral particles.

4. Consistent with this hypothesis, viral production was strongly affected by host C : P ratio. While host C : P ratio did not affect viral attachment or the percentage of new viral particles that were infectious, in the low C : P Chlorella NC64A treatment, nine times more viruses were produced per infected cell than in the high C : P treatment (158 ± 138 versus 18 ± 18), indicating that the low C : P cells were higher quality for PBCV‐1 proliferation.

5. This result implies that the stoichiometric quality of algal cells can have a major effect on host–virus population dynamics.
Brown trout and food web interactions in a Minnesota stream
Authors: ZIMMERMAN JULIE K. H. , VONDRACEK BRUCE
Published: November 2006

1. We examined indirect, community‐level interactions in a stream that contained non‐native brown trout (Salmo trutta Linnaeus), native brook trout (Salvelinus fontinalis Mitchill) and native slimy sculpin (Cottus cognatus Richardson). Our objectives were to examine benthic invertebrate composition and prey selection of fishes (measured by total invertebrate dry mass, dry mass of individual invertebrate taxa and relative proportion of invertebrate taxa in the benthos and diet) among treatments (no fish, juvenile brook trout alone, juvenile brown trout alone, sculpin with brook trout and sculpin with brown trout).

2. We assigned treatments to 1 m2 enclosures/exclosures placed in riffles in Valley Creek, Minnesota, and conducted six experimental trials. We used three designs of fish densities (addition of trout to a constant number of sculpin with unequal numbers of trout and sculpin; addition of trout to a constant number of sculpin with equal numbers of trout and sculpin; and replacement of half the sculpin with an equal number of trout) to investigate the relative strength of interspecific versus intraspecific interactions.

3. Presence of fish (all three species, alone or in combined‐species treatments) was not associated with changes in total dry mass of benthic invertebrates or shifts in relative abundance of benthic invertebrate taxa, regardless of fish density design.

4. Brook trout and sculpin diets did not change when each species was alone compared with treatments of both species together. Likewise, we did not find evidence for shifts in brown trout or sculpin diets when each species was alone or together.

5. We suggest that native brook trout and non‐native brown trout fill similar niches in Valley Creek. We did not find evidence that either species had an effect on stream communities, potentially due to high invertebrate productivity in Valley Creek.
The influence of biotope availability on macroinvertebrate assemblages in South African rivers: implications for aquatic bioassessment
Authors: DALLAS HELEN F.
Published: November 2006

1. Macroinvertebrate biotope preferences and the influence of differences in the availability of biotopes on individual taxa, macroinvertebrate assemblages and a biotic index, the South African Scoring System (SASS), were investigated in two regions of South Africa.

2. Among biotope differences in individual taxa and macroinvertebrate assemblages resulted in differences in SASS scores, with differences in assemblages being greater among biotopes than between sites.

3. All three metrics studied (SASS score, number of taxa and average score per taxon, ASPT), differed significantly among biotopes, with highest scores consistently recorded in the stones biotope, while lowest SASS scores and fewest taxa were recorded in the sand biotope.

4. SASS score and number of taxa were positively, while ASPT was negatively correlated with number of biotopes sampled.

5. The observed biotope differences highlight the importance of sampling and comparing data from sites separately for each biotope.
Challenges to estimating carbon emissions from tropical deforestation
Authors: RAMANKUTTY NAVIN , GIBBS HOLLY K. , ACHARD FRÉDÉRIC , DEFRIES RUTH , FOLEY JONATHAN A. , HOUGHTON R. A.
Published: November 2006

An accurate estimate of carbon fluxes associated with tropical deforestation from the last two decades is needed to balance the global carbon budget. Several studies have already estimated carbon emissions from tropical deforestation, but the estimates vary greatly and are difficult to compare due to differences in data sources, assumptions, and methodologies. In this paper, we review the different estimates and datasets, and the various challenges associated with comparing them and with accurately estimating carbon emissions from deforestation. We performed a simulation study over legal Amazonia to illustrate some of these major issues. Our analysis demonstrates the importance of considering land‐cover dynamics following deforestation, including the fluxes from reclearing of secondary vegetation, the decay of product and slash pools, and the fluxes from regrowing forest. It also suggests that accurate carbon‐flux estimates will need to consider historical land‐cover changes for at least the previous 20 years. However, this result is highly sensitive to estimates of the partitioning of cleared carbon into instantaneous burning vs. long‐timescale slash pools. We also show that carbon flux estimates based on ‘committed flux’ calculations, as used by a few studies, are not comparable with the ‘annual balance’ calculation method used by other studies.
Functional characterization of a T‐cell receptor BV6+ T‐cell clone derived from a leprosy lesion
Authors: Sabet Shereen , Ochoa Maria‐Teresa , Sieling Peter A. , Rea Thomas H. , Modlin Robert L.
Published: November 2006

Human infection with Mycobacterium leprae, an intracellular bacterium, presents as a clinical and immunological spectrum; thus leprosy provides an opportunity to investigate mechanisms of T‐cell responsiveness to a microbial pathogen. Analysis of the T‐cell receptor (TCR) repertoire in leprosy lesions revealed that TCR BV6+ T cells containing a conserved CDR3 motif are over‐represented in lesions from patients with the localized form of the disease. Here, we derived a T‐cell clone from a leprosy lesion that expressed TCR BV6 and the conserved CDR3 sequence L‐S‐G. This T‐cell clone produced a T helper type 1 cytokine pattern, directly lysed M. leprae‐pulsed antigen‐presenting cells by the granule exocytosis pathway, and expressed the antimicrobial protein granulysin. BV6+ T cells may therefore functionally contribute to the cell‐mediated immune response against M. leprae.
Degradation of trans‐polyisoprene over time following the analysis of root fillings removed during conventional retreatment
Authors: Maniglia‐Ferreira C. , Silva J. B. A. , De Paula R. C. M. , Feitosa J. P. A. , Zaia A. A. , Ferraz C. C. R. , Gomes B. P. F. A. , Souza‐Filho F. J.
Published: November 2006

Aim  To evaluate in vivo degradation of root filling materials over time.

Methodology  Thirty‐six root filled teeth with or without periapical lesions were selected. Teeth with poor coronal restoration were not included. The teeth had been root filled 3–30 years previous and were scheduled for conventional retreatment. The association of root canal treatment, age, periapical lesion and root filling degradation was investigated. The filling material was removed from the root canal using files and no solvent. Trans‐1,4‐polyisoprene was isolated through solubilization of root filling remnants in chloroform followed by filtration and centrifugation. Gel permeation chromatography (GPC) and infrared spectroscopy (FT‐IR) were utilized to study the occurrence and degree of degradation. The GPC and FT‐IR data were collected for each sample and analysed statistically using the Kruskal–Wallis test.

Results  Degradation of trans‐1,4‐polyisoprene was a slow process. The process was identified as an oxidation reaction through the production of carboxyl and hydroxyl groups. Compared with the control group, significant molar mass decrease was noted after 15 years (P = 0.0146) in teeth with no periapical lesions. However, in teeth associated with periapical lesions the number of years for significant degradation was reduced to 5 (P = 0.0009).

Conclusion  Polyisoprene degrades inside root canals as an oxidative process. The presence of periapical lesions was associated with a more rapid onset of degradation.
Antibacterial efficacy of calcium hydroxide intracanal dressing: a systematic review and meta‐analysis
Authors: Sathorn C. , Parashos P. , Messer H.
Published: November 2006

Aim  To determine to what extent does calcium hydroxide intracanal medication eliminate bacteria from human root canals, compared with the same canals before medication, as measured by the number of positive cultures, in patients undergoing root canal treatment for apical periodontitis (teeth with an infected root canal system).

Methodology  CENTRAL, MEDLINE and EMBASE databases were searched. Reference lists from identified articles were scanned. A forward search was undertaken on the authors of the identified articles. Papers that had cited these articles were also identified through the Science Citation Index to identify potentially relevant subsequent primary research.

Review methods  The included studies were pre‐/post‐test clinical trials comparing the number of positive bacterial cultures from treated canals. Data in those studies were independently extracted. Risk differences of included studies were combined using the generic inverse variance and random effect method.

Results  Eight studies were identified and included in the review, covering 257 cases. Sample size varied from 18 to 60 cases; six studies demonstrated a statistically significant difference between pre‐ and post‐medicated canals, whilst two did not. There was considerable heterogeneity among studies. Pooled risk difference was −21%; 95% CI: −47% to 6%. The difference between pre‐ and post‐medication was not statistically significant (P = 0.12).

Conclusions  Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal when assessed by culture techniques.