bluuebunny/crossref_metadata_2025 huggingface dataset:
'A posteriori' searching for phenotypic characters to describe new cryptic species of sponges revealed by molecular markers (Dictyonellidae : Scopalina)
Authors: Blanquer Andrea , Uriz Maria-J.
Published: December 2008

Cryptic speciation is repeatedly reported in sponge taxonomic studies. Most of the cryptic species, which were revealed by molecular markers, have never been formally described owing to the difficulty in finding diagnostic phenotypic characters. A previous molecular study revealed four genetically distinct species that had been misidentified as Scopalina lophyropoda Schmidt. One species was S. lophyropoda sensu stricto, whereas the other three were new species. Here, the three new species are formally described after careful searching for discriminatory phenotypic characters. The new species are Scopalina blanensis, sp. nov. from the north-western Mediterranean, S. ceutensis, sp. nov. from the Mediterranean coasts of Africa (Atlantic waters) and S. canariensis, sp. nov. from the Canary Islands, Atlantic Ocean. All of them are at first sight morphologically similar and inhabit shallow environments with resuspended sediment. However, a closer examination allowed us to find some differential features: e.g. the amount of spongin embedding the spicules, the degree of complexity of the skeletal tracts, the size and curvature of the styles, the growth habit and the colour tinge. Furthermore, an identification key to the Atlanto-Mediterranean Scopalina species is presented. The differences between the genera Scopalina, Ulosa and Dictyonella are also discussed.
Cloning endangered felids using heterospecific donor oocytes and interspecies embryo transfer
Authors: Gómez Martha C. , Pope C. Earle , Ricks David M. , Lyons Justine , Dumas Cherie , Dresser Betsy L.
Published: December 2008

Somatic cell nuclear transfer (SCNT) offers the possibility of preserving endangered species. It is one of the few technologies that avoids the loss of genetic variation and provides the prospect of species continuance, rather than extinction. Nonetheless, there has been a debate over the use of SCNT for preserving endangered species because of abnormal nuclear reprogramming, low efficiency and the involvement of extra mitochondrial DNA (mtDNA) of a different species in live offspring produced by interspecies SCNT. Despite these limitations, live endangered cloned animals have been produced. In the present paper, we describe recent research on the production of cloned embryos derived by fusion of wild felid fibroblast cells with heterospecific domestic cat cytoplasts and their viability after transfer into domestic cat recipients. In addition, we discuss epigenetic events that take place in donor cells and felid cloned embryos and mtDNA inheritance in wild felid clones and their offspring.
Amyloid-β overproduction causes abnormal mitochondrial dynamics via differential modulation of mitochondrial fission/fusion proteins
Authors: Wang Xinglong , Su Bo , Siedlak Sandra L. , Moreira Paula I. , Fujioka Hisashi , Wang Yang , Casadesus Gemma , Zhu Xiongwei
Published: December 2008

Mitochondrial dysfunction is a prominent feature of Alzheimer disease but the underlying mechanism is unclear. In this study, we investigated the effect of amyloid precursor protein (APP) and amyloid β on mitochondrial dynamics in neurons. Confocal and electron microscopic analysis demonstrated that ≈40% M17 cells overexpressing WT APP (APPwt M17 cells) and more than 80% M17 cells overexpressing APPswe mutant (APPswe M17 cells) displayed alterations in mitochondrial morphology and distribution. Specifically, mitochondria exhibited a fragmented structure and an abnormal distribution accumulating around the perinuclear area. These mitochondrial changes were abolished by treatment with β-site APP-cleaving enzyme inhibitor IV. From a functional perspective, APP overexpression affected mitochondria at multiple levels, including elevating reactive oxygen species levels, decreasing mitochondrial membrane potential, and reducing ATP production, and also caused neuronal dysfunction such as differentiation deficiency upon retinoic acid treatment. At the molecular level, levels of dynamin-like protein 1 and OPA1 were significantly decreased whereas levels of Fis1 were significantly increased in APPwt and APPswe M17 cells. Notably, overexpression of dynamin-like protein 1 in these cells rescued the abnormal mitochondrial distribution and differentiation deficiency, but failed to rescue mitochondrial fragmentation and functional parameters, whereas overexpression of OPA1 rescued mitochondrial fragmentation and functional parameters, but failed to restore normal mitochondrial distribution. Overexpression of APP or Aβ-derived diffusible ligand treatment also led to mitochondrial fragmentation and reduced mitochondrial coverage in neuronal processes in differentiated primary hippocampal neurons. Based on these data, we concluded that APP, through amyloid β production, causes an imbalance of mitochondrial fission/fusion that results in mitochondrial fragmentation and abnormal distribution, which contributes to mitochondrial and neuronal dysfunction.
Identification of Barkor as a mammalian autophagy-specific factor for Beclin 1 and class III phosphatidylinositol 3-kinase
Authors: Sun Qiming , Fan Weiliang , Chen Keling , Ding Xiaojun , Chen She , Zhong Qing
Published: December 2008

Autophagy mediates the cellular response to nutrient deprivation, protein aggregation, and pathogen invasion in human. Dysfunction of autophagy has been implicated in multiple human diseases including cancer. The identification of novel autophagy factors in mammalian cells will provide critical mechanistic insights into how this complicated cellular pathway responds to a broad range of challenges. Here, we report the cloning of an autophagy-specific protein that we called Barkor (Beclin 1-associated autophagy-related key regulator) through direct interaction with Beclin 1 in the human phosphatidylinositol 3-kinase class III complex. Barkor shares 18% sequence identity and 32% sequence similarity with yeast Atg14. Elimination of Barkor expression by RNA interference compromises starvation- and rapamycin-induced LC3 lipidation and autophagosome formation. Overexpression of Barkor leads to autophagy activation and increased number and enlarged volume of autophagosomes. Tellingly, Barkor is also required for suppression of the autophagy-mediated intracellular survival of
Salmonella typhimurium
in mammalian cells. Mechanistically, Barkor competes with UV radiation resistance associated gene product (UVRAG) for interaction with Beclin 1, and the complex formation of Barkor and Beclin1 is required for their localizations to autophagosomes. Therefore, we define a regulatory signaling pathway mediated by Barkor that positively controls autophagy through Beclin 1 and represents a potential target for drug development in the treatment of human diseases implicated in autophagic dysfunction.
Short Article: What is Learned about Fragments in Artificial Grammar Learning? A Transitional Probabilities Approach
Authors: Poletiek Fenna H. , Wolters Gezinus
Published: December 2008

Learning local regularities in sequentially structured materials is typically assumed to be based on encoding of the frequencies of these regularities. We explore the view that transitional probabilities between elements of chunks, rather than frequencies of chunks, may be the primary factor in artificial grammar learning (AGL). The transitional probability model (TPM) that we propose is argued to provide an adaptive and parsimonious strategy for encoding local regularities in order to induce sequential structure from an input set of exemplars of the grammar. In a variant of the AGL procedure, in which participants estimated the frequencies of bigrams occurring in a set of exemplars they had been exposed to previously, participants were shown to be more sensitive to local transitional probability information than to mere pattern frequencies.
Orthogonal representations of twisted forms of 𝑆𝐿₂
Authors: Garibaldi Skip
Published: December 2008

For every absolutely irreducible orthogonal representation of a twisted form of

SL
2

\operatorname {SL}_2

over a field of characteristic zero, we compute the “unique” symmetric bilinear form that is invariant under the group action. We also prove the analogous result for Weyl modules in prime characteristic (including characteristic 2) and an isomorphism between two symmetric bilinear forms given by binomial coefficients.
The Cap Roux MPA (Saint-Raphaël, French Mediterranean): changes in fish assemblages within four years of protection
Authors: Seytre Catherine , Francour Patrice
Published: December 2008

Seytre, C., and Francour, P. 2009. The Cap Roux MPA (Saint-Raphaël, French Mediterranean): changes in fish assemblages within four years of protection. – ICES Journal of Marine Science, 66: 180–187. In recent decades, marine reserves have been established to protect ecosystem structure and biological diversity, or as management tools to combat the overexploitation of fish stocks. The Cap Roux Marine Protected Area (MPA) was established by professional fishers in December 2003, in the French Mediterranean between Cannes and Saint-Raphaël. It was implemented to enhance target fish stocks for local fisheries. The objective of this 3-year study was to investigate the initial responses of fish assemblages, using complementary methods: experimental net fishing performed by a professional fisher and underwater visual census. Within 3 years, this study detected early changes in the fish assemblages. The methods also detected an increase in abundance and diversity of fish, but also a decrease of seasonal fluctuations of the assemblage structure, which was characterized by winter values close to summer values in the protected zone but not outside of the MPA. These results helped clarify the dynamic by which fish assemblages respond to fishing prohibition in a newly created protected area.
Evolution and evolvability: celebrating Darwin 200
Authors: Brookfield John F.Y
Published: December 2008

The concept of ‘evolvability’ is increasingly coming to dominate considerations of evolutionary change. There are, however, a number of different interpretations that have been put on the idea of evolvability, differing in the time scales over which the concept is applied. For some, evolvability characterizes the potential for future adaptive mutation and evolution. Others use evolvability to capture the nature of genetic variation as it exists in populations, particularly in terms of the genetic covariances between traits. In the latter use of the term, the applicability of the idea of evolvability as a measure of population's capacity to respond to natural selection rests on one, but not the only, view of the way in which we should envisage the process of natural selection. Perhaps the most potentially confusing aspects of the concept of evolvability are seen in the relationship between evolvability and robustness.
Time-periodic solutions to a nonlinear wave equation with periodic or anti-periodic boundary conditions
Authors: Ji Shuguan
Published: December 2008

This paper is concerned with the existence of time-periodic solutions to the nonlinear wave equation with
x
-dependent coefficients
u
(
x
)
y

tt

−
(
u
(
x
)
y

x

)

x

+
au
(
x
)
y
+|
y
|

p
−2

y
=
f
(
x
, 
t
) on (0, 
π
)×

under the periodic or anti-periodic boundary conditions
y
(0,
t
)=±
y
(
π
, 
t
),
y

x

(0, 
t
)=±
y

x

(
π
, 
t
) and the time-periodic conditions
y
(
x
, 
t
+
T
)=
y
(
x
, 
t
),
y

t

(
x
, 
t
+
T
)=
y

t

(
x
, 
t
). Such a model arises from the forced vibrations of a non-homogeneous string and the propagation of seismic waves in non-isotropic media. A main concept is the notion ‘weak solution’ to be given in §2. For
T
=2
π
/
k
(
k
∈

), we establish the existence of time-periodic solutions in the weak sense by investigating some important properties of the wave operator with
x
-dependent coefficients.
ACDP– a Java application for data processing and analysis of protein circular dichroism spectra
Authors: Hofmann A.
Published: December 2008

ACDPis a Java application for processing protein circular dichroism (CD) spectra either individually or within a series. Data processing includes spectrum subtraction (`baseline correction'), conversion of the raw CD into units of mean residue ellipticity, wavelength monitoring and graphical inspection. Three different algorithms for secondary structure deconvolution have been implemented, and spectra can be analysed without the need for data reformatting, using a neural network approach, variable selection or linear combination of prototype spectra. The application is written entirely in Java and is thus portable to a wide variety of platforms, requiring only the Java Runtime Environment.
Experimental autoimmune uveoretinitis initiated by non‐phagocytic destruction of inner segments of photoreceptor cells by Mac‐1+ mononuclear cells
Authors: Miura‐Takeda Sayako , Tashiro‐Yamaji Junko , Oku Hidehiro , Takahashi Takeshi , Shimizu Tetsunosuke , Sugiyama Tetsuya , Ikeda Tsunehiko , Kubota Takahiro , Yoshida Ryotaro
Published: December 2008

EAU in mice is a model of human posterior uveitis. EAU is a Th1‐dependent disease that has been assumed to target the neural retina and related tissues; however, in situ effector cells and the target have not yet been clearly demonstrated. In the present study, we induced EAU in B10R mice by immunizing them with human interphotoreceptor retinoid‐binding protein peptide 161–180. Histological examinations revealed that EAU occurred approximately 11 days after the immunization and reached a peak on day 14. Retinae from normal or EAU mice were treated with proteases to obtain mono‐dispersed cells. The mono‐dispersed cells thus obtained were separated into three to four fractions by discontinuous Percoll density‐gradient (e.g. PBS/40/60) centrifugation. In normal mice, 94% of the total cells were recovered in two fractions (i.e. PBS/40 and pellet); and these fractions mainly contained inner and outer segments and cell bodies of photoreceptor cells and RPE cells, respectively. In EAU mice, additional cells (i.e. inflammatory cells) were obtained at the 40/60 interface. Electron microscopic examination showed that tissue damage during EAU was initiated by non‐phagocytic destruction of inner segments by Mac‐1+ mononuclear cells on day 11, followed by phagocytic activity of macrophages against outer segments and RPE cells on day 14. In vitro culturing of normal retinal cells with EAU infiltrates suggested the involvement of TNF‐α and NO in the tissue damage. These results indicate that EAU was initiated by non‐phagocytic destruction of inner segments of photoreceptor cells by Mac‐1+ mononuclear cells.
Multivariate analysis of febrile neutropenia occurrence in patients with non‐Hodgkin lymphoma: data from the INC‐EU Prospective Observational European Neutropenia Study
Authors: Pettengell Ruth , Bosly André , Szucs Thomas D. , Jackisch Christian , Leonard Robert , Paridaens Robert , Constenla Manuel , Schwenkglenks Matthias ,   for the Impact of Neutropenia in Chemotherapy ‐ European Study Group (INC‐EU)
Published: December 2008

Myelosuppression, particularly febrile neutropenia (FN), are serious dose‐limiting toxicities that occur frequently during the first cycle of chemotherapy. Identifying patients most at risk of developing FN might help physicians to target prophylactic treatment with colony‐stimulating factor (CSF), in order to decrease the incidence, or duration, of myelosuppression and facilitate delivery of chemotherapy as planned. We present a risk model for FN occurrence in the first cycle of chemotherapy, based on a subgroup of 240 patients with non‐Hodgkin lymphoma (NHL) enroled in our European prospective observational study. Eligible patients had an International Prognostic Index of 0–3, and were scheduled to receive a new myelosuppressive chemotherapy regimen with at least four cycles. Clinically relevant factors significantly associated with cycle 1 FN were older age, increasing planned cyclophosphamide dose, a history of previous chemotherapy, a history of recent infection, and low baseline albumin (<35 g/l). Prophylactic CSF use and higher weight were associated with a significant protective effect. The model had high sensitivity (81%) and specificity (80%). Our model, together with treatment guidelines, may rationalise the clinical decision of whether to support patients with CSF primary prophylaxis based on their risk factor profile. Further validation is required.
The prevention of hospital‐acquired venous thromboembolism in the United Kingdom
Authors: Hunt Beverley J.
Published: December 2008

Hospital‐acquired venous thromboembolism (VTE) remains the number one safety issue in hospitals and is estimated to cause more preventable deaths than the more publicized hospital‐acquired infection. There has been a failure of implementation of thromboprophylaxis (TP), mainly because of lack of awareness among health professionals, despite the large number of evidence‐based studies available. The situation in the UK is gradually changing because of tireless campaigning by politicians, a charity and key opinion leaders. In response, the Department of Health has issued a national risk assessment tool, and National Institute of Clinical Excellence (NICE) guidelines for the prevention of VTE in all hospitalised patients, which will be available in August 2009. Although NICE guidelines are only applicable in England, it is to be hoped Northern Ireland, Wales and Scotland will also follow. Despite this, the consensus of expert opinion is that TP needs mandating to prevent pockets of non‐adherence. Low molecular weight heparins are currently the gold standard pharmacological agent for TP; but are likely to be superseded within the next 5 years by new classes of oral anticoagulants, such as dabigatran and rivaroxiban, which are already licensed for TP after orthopaedic surgery.
Successful treatment of verruca plantaris with a single sublesional injection of interferon-α2a
Authors: Aksakal A. A. , Ozden M. G. , Atahan C. , Onder M.
Published: December 2008

Background. Interferons are molecules with antiviral effects, which have been used for the treatment of verruca for many years.

Aims. To determine if sublesional interferon (IFN)-α injection offers an effective alternative treatment for common warts.

Methods. We compared the results of single-dose sublesional IFN application in different types of verruca and with placebo for the treatment of single verruca plantaris lesions. In total, 53 patients (mean age 22.6 years) were enrolled in the study. Of these, 45 patients received a single sublesional injection of 4.5 MU IFN-α2a (three study groups), and eight patients with single verruca plantaris lesions were injected with physiological saline as placebo (control group). As local anaesthesia, liquid nitrogen was sprayed only on to the injection site for 3–4 s. The injection was made directly under the lesion through the border of the lesion, at with approximately a 45° angle from healthy skin.

Results. At the 12-month follow-up in the group of patients with single verruca plantaris, there were 19 complete cures (7.2%) and 2 partial responses (8.3%), and 3 patients (12.5%) had no response. In the control group, only 2 patients (25%) had a partial response to treatment.

Conclusions. These results suggest that a single sublesional dose of 4.5 MU IFN-α may be of value in the treatment of patients with verruca, especially in those with single verruca plantaris lesions.
Use of a GH receptor antagonist (GHRA) to explore the relationship between GH and IGF‐I in adults with severe GH deficiency (GHD)
Authors: Berg C. A. , Pokrajac A. , Bidlingmaier M. , Strasburger C. J. , Shalet S. M. , Trainer P. J.
Published: December 2008

Objective  At diagnosis, approximately 50% of adults with severe GH deficiency (GHD) have an IGF‐I within the reference range. It is unclear whether in such patients serum IGF‐I levels are regulated by factors other than GH.

Design and patients  We performed a double‐blind, randomized, placebo‐controlled, cross‐over study to investigate the effect of the GH receptor antagonist – pegvisomant (20 mg daily for 14 days) on GH and IGF‐I levels in three cohorts: patients with GHD and a normal IGF‐I (NORMS); patients with GHD and a low IGF‐I (LOWS) and healthy volunteers (CONS).

Results  Pegvisomant decreased IGF‐I in CONS and NORMS [158·5 (101–206) vs. 103 (77–125) µg/l, P < 0·01; 124 (81–136) vs. 95 (51–113) µg/l, P < 0·01 respectively], but not in LOWS [31 (< 31–32) vs. 34·5 (< 31–38) µg/l], and this was associated with an increase in mean 24 h GH in CONS [0·49 (0·12–0·89) to 1·38 (0·22–2·45) µg/l (P = 0·03)] and in NORMS [69 (0–320)% from 0·1 (< 0·1–0·13) to 0·17 (0·11–0·42) µg/l (P = 0·03)], but not in the LOWS. The peak GH response to arginine was increased by pegvisomant in CONS and NORMS [6·1 (0·8–9) vs. 20·4 (13·1–28·8) µg/l, P = 0·03; 0·4 (0·1–0·5) vs. 0·5 (0·3–0·6) µg/l, respectively], but not in LOWS.

Conclusions  These data indicate that patients with severe GHD with a normal IGF‐I are able to increase GH secretion in response to a pegvisomant‐induced fall in IGF‐I, whereas those with low IGF‐I levels are unable to increase GH secretion. Therefore circulating IGF‐I appears to be GH‐independent in GHD patients with a low IGF‐I, but remains partially GH‐dependant in GHD patients with a normal IGF‐I.
Peroxisome proliferator‐activated receptor γ (PPAR) agonism reduces the insulin‐stimulated increase in circulating interleukin‐6 in GH replaced GH‐deficient adults
Authors: Krag Morten B. , Rasmussen Lars M. , Hansen Troels K. , Frystyk Jan , Flyvbjerg Allan , Møller Niels , Jørgensen Jens O. L.
Published: December 2008

Context  Peroxisome proliferator‐activated receptor γ (PPARγ) agonists modify cardiovascular risk factors and inflammatory markers in patients with type 2 diabetes. GH treatment in GH‐deficient (GHD) patients may cause insulin resistance and exerts ambiguous effects on inflammatory markers.

Objective  To investigate circulating markers of inflammation and endothelial function in GH replaced GHD patients before and after 12 weeks administration of either pioglitazone 30 mg/day (N = 10) or placebo (N = 10) in a randomized double‐blind parallel design.

Methods  Circulating levels of interleukins (ILs)‐1β, IL‐2, IL‐4, IL‐6, IL‐8, IL‐10, tumour necrosis factor (TNF)‐α, high sensitivity C‐reactive protein, vascular cell adhesion molecule‐I, and osteoprotegerin (OPG) were measured in the basal state and after a 2·5 h hyperinsulinaemic euglycaemic clamp.

Results  Insulin sensitivity improved in the group receiving PPARγ agonist (P = 0·03). Serum IL‐6 levels increased by 114 ± 31% (mean ± SE) in the entire group (N = 20) following the hyperinsulinaemic euglycaemic clamp (P = 0·01) performed at study start. Twelve weeks of PPARγ agonist treatment significantly abrogated this insulin‐stimulated increment in IL‐6 levels compared to placebo (P = 0·01). Furthermore PPARγ agonist treatment significantly lowered basal IL‐4 levels (P < 0·05).

Conclusions  (i) IL‐6 levels increase during a hyperinsulinaemic clamp in GH replaced patients (ii) This increase in IL‐6 is abrogated by PPARγ agonist treatment (iii) we hypothesize that PPARγ agonist‐induced improvement of insulin sensitivity may obviate a compensatory rise in IL‐6.
Low O6‐methylguanine‐DNA methyltransferase (MGMT) expression and response to temozolomide in aggressive pituitary tumours
Authors: McCormack Ann I. , McDonald Kerrie L. , Gill Anthony J. , Clark Susan J. , Burt Morton G. , Campbell Kirsten A. , Braund Wilton J. , Little Nicholas S. , Cook Raymond J. , Grossman Ashley B. , Robinson Bruce G. , Clifton‐Bligh Roderick J.
Published: December 2008

Context  Recent case reports detail the successful use of temozolomide in the management of aggressive pituitary tumours. O6‐methylguanine‐DNA methyltransferase (MGMT) is a DNA repair protein that counteracts the effect of temozolomide.

Objective  To study MGMT expression in pituitary tumours and consider whether MGMT expression is associated with response to temozolomide therapy in aggressive pituitary tumours.

Patients  We report two patients with aggressive pituitary tumours treated with temozolomide, one who responded to temozolomide and the other who did not. MGMT expression was assessed in a further 88 archived pituitary tumour samples.

Design  MGMT expression was assessed by immunohistochemistry. MGMT promoter methylation was studied by methylation‐specific polymerase chain reaction (MSP), sequencing of MGMT was performed and loss of heterozygosity (LOH) analysis undertaken.

Results  Low MGMT expression and MGMT promoter methylation were found in the pituitary tumour of the patient who responded to temozolomide. Conversely, high MGMT expression was seen in the patient demonstrating a poor response to temozolomide. Eleven out of 88 archived tumour samples (13%) had low MGMT expression. Prolactinomas were more likely to have low MGMT expression compared with other pituitary tumour subtypes (P < 0·001). There was no significant difference in MGMT expression between invasive and noninvasive tumours, or between recurrent and nonrecurrent tumours. A significant inverse correlation was found between MGMT expression and promoter methylation (P = 0·012).

Conclusion  MGMT expression as assessed by immunohistochemistry may predict response to temozolomide therapy in patients with aggressive pituitary tumours. MGMT promoter methylation is likely to explain low MGMT expression in some, but not all, pituitary tumours.
Beta‐adrenergic agonism does not impair the GH response to acylated ghrelin in humans
Authors: Benso A. , Gramaglia E. , Prodam F. , Riganti F. , Gigliardi V. Ramella , Lucatello B. , Olivetti I. , St Pierre D. , Ghigo E. , Broglio F.
Published: December 2008

Background  Acylated ghrelin (AG) is a physiological GH secretion amplifier, in part stimulating GHRH neurones and antagonizing somatostatin activity. In humans, AG is one of the most potent pharmacological stimuli of GH secretion and, unlike GHRH, is refractory to the inhibitory effect of glucose, free fatty acids (FFA) and somatostatin. Somatotroph secretion is also profoundly modulated by the adrenergic system. Indeed, beta‐adrenergic agonists abolish spontaneous and GHRH‐stimulated GH secretion. Based on these data, the aim of the present study was to investigate the effects of beta adrenergic agonism on the GH response to AG.

Subjects and measurements  Six young healthy male volunteers underwent: (a) acute AG intravenous (iv) administration (1·0 µg/kg); (b) salbutamol infusion (SLB; 0·06 µg/kg/min iv); (c) AG + SLB; and (d) saline infusion. In all sessions GH levels were assayed every 15 min from time –30 to +210 min.

Results  SLB induced a significant (P < 0·05) inhibition of spontaneous GH secretion that persisted up to 75 min after SLB withdrawal. AG induced a marked increase (P < 0·01) in GH that was not modified by SLB.

Conclusions  The GH‐releasing effect of AG is refractory to the inhibitory effect of SLB‐induced beta‐adrenergic receptor activation. Although further studies are needed to confirm these results during the lifespan and particularly during prolonged exposure to beta agonists, the present data clearly suggest that, among GH stimulatory tests, AG administration might be the most suitable in clinical conditions of chronic treatment with beta‐2 agonists, such as in asthmatic disease.
Modelling changes in soil organic matter after planting fast‐growingPinus radiataon Mediterranean agricultural soils
Authors: Romanyà J. , Cortina J. , Falloon P. , Coleman K. , Smith P.
Published: December 2008

The Kyoto Protocol explicitly allows the storage of carbon (C) in ecosystems resulting from afforestation to be offset against a nation's carbon emissions and paves the way for carbon storage in soils to be eligible as carbon offsets in the future. More information is required about how afforestation affects carbon storage, especially in the soil. We report a study in which soil carbon storage in first‐rotation MediterraneanPinus radiataplantations, established on former cereal fields and vineyards, was measured and modelled. Measurements were made on plantations of several ages, as well as repeat measurements at the same site after 5 years. We tested the ability of two widely used soil organic matter models (RothC and Century) to predict carbon sequestration in Mediterranean forest soils.

Increases in the top 5 cm of soil of about 10 g C m−2 year−1were observed after afforestation of former vineyards, but nitrogen (N) either remained the same or decreased slightly. During afforestation, most organic matter accumulated in the ectorganic layers at a rate of 19 g C m−2 year−1in former vineyards and 41 g C m−2 year−1in former cereal fields. The RothC and Century models were sensitive to previous land use and estimated a carbon sequestration potential over 20 years of 950 and 700 g C m−2, respectively. The accurate simulation of the dynamics of soil organic matter by RothC, together with measured above‐ground inputs, allowed us to calculate below‐ground inputs during afforestation. The Century model simulated total C and N, including the ectorganic horizons, well. Simulations showed a depletion of N in the below‐ground fractions during afforestation, with N limitation in the former vineyard but not on former cereal land. The approach demonstrates the potential of models to enhance our understanding of the processes leading to carbon sequestration in soils.
Distribution of microbial biomass and phospholipid fatty acids in Podzol profiles under coniferous forest
Authors: Fritze H. , Pietikäinen J. , Pennanen T.
Published: December 2008

Microbial‐derived phospholipid fatty acids (PLFAs) can be used to characterize the microbial communities in soil without the need to isolate individual fungi and bacteria. They have been used to assess microbial communities of humus layers under coniferous forest, but nothing is known of their distribution in the deeper soil. To investigate the vertical distribution we sampled nine Podzol profiles on a 100‐m‐long transect in a coniferous forest and analysed for their microbial biomass and PLFA pattern to a depth of 0.4 m. The transect covered a fertility gradient from Vaccinium vitis‐idaea forest site type to Vaccinium myrtillus forest site type. The cores were divided into humus (O) and eluvial (E) layers and below that into 10‐cm sections and designated as either illuvial (B) or parent material (C), or as a combination (BC). Two measures of microbial biomass analyses were applied: substrate‐induced respiration (SIR) to determine microbial biomass C (Cmic), and the sum of the extracted microbial‐derived phospholipid fatty acids (totPLFA). The soil fertility had no effect on the results. The Cmic correlated well with totPLFA (r= 0.86). The microbial biomass decreased with increasing depth. In addition the PLFA pattern changed with increased depth as assessed with principal component analysis, indicating a change in the microbial community structure. The composition of the PLFAs in the O layer differed from that in the E layer and both differed from the upper part of the B layer and from the rest of the BC layers. The deeper parts of the B layer (BC1, BC2 and BC3) were similar to one other. The O layer had more 18:2ω6, a PLFA indicator of fungi, whereas the E layer contained relatively more of the PLFAs 16:1ω9, 18:1ω7 and cy19:0 common in gram‐negative bacteria. With increased depth the relative amount of 10Me18:0, the PLFA indicator for actinomycetes, increased. We conclude that the PLFA method is a promising discriminator between the microbial community structures of the horizons in Podzols.
Interactions of aluminium and fulvic acid in moderately acid solutions: stoichiometry of the H+/Al3+ exchange
Authors: Simonsson M.
Published: December 2008

Complexation with organic matter controls the activity of dissolved Al3+ in many soils. The buffering intensity of these soils is largely dependent on the H+/Al3+ exchange ratio, i.e. the number of protons consumed by the solid phase when one Al3+ is released. Here, the H+/Al3+ exchange ratio was determined from batch titrations using solutions of fulvic acid (FA) as a model for soil organic matter. Aluminium was added, from 1.04 to 6.29 mmol Al per g FA, which is within the range of humus‐bound Al found in the upper B horizon of podzolized soils. Furthermore, pH was varied with NaOH to give values between 3.5 and 5.0. The H+/Al3+ exchange ratio ranged between 1.49 and 2.23 with a mean of 1.94. It correlated positively with pH and the total concentration of Al present. Theoretically, this can be explained with a partial hydrolysis of bound Al. The slope of logAl (log10 of Al3+ activity) against pH generally underestimated the actual exchange ratio, which can partly be attributed to the systems being diluted (100 mg FA l−1). However, where 4 mmol Al or more had been added per g FA, the logAl slope gradually approached −3 between pH 4.5 and 5.0. This might be the result of a shift from Al3+ activity control by humus complexation to control by Al(OH)3(s).
Towards a predictive framework for predator risk effects: the interaction of landscape features and prey escape tactics
Authors: Heithaus Michael R. , Wirsing Aaron J. , Burkholder Derek , Thomson Jordan , Dill Lawrence M.
Published: December 2008

Risk effects of predators can profoundly affect community dynamics, but the nature of these effects is context dependent.

Although context dependence has hindered the development of a general framework for predicting the nature and extent of risk effects, recent studies suggest that such a framework is attainable if the factors that shape anti‐predator behaviour, and its effectiveness, in natural communities are well understood.

One of these factors, the interaction of prey escape tactics and landscape features, has been largely overlooked.

We tested whether this interaction gives rise to interspecific variation in habitat‐use patterns of sympatric large marine vertebrates at risk of tiger shark (Galeocerdo cuvier Peron and LeSueur, 1822) predation. Specifically, we tested the a priori hypothesis that pied cormorants (Phalacrocorax varius Gmelin, 1789) would modify their use of shallow seagrass habitats in a manner opposite to that of previously studied dolphins (Tursiops aduncus Ehrenberg, 1833), dugongs (Dugong dugon Müller, 1776), and green turtles (Chelonia mydas Linnaeus, 1758) because, unlike these species, the effectiveness of cormorant escape behaviour does not vary spatially.

As predicted, cormorants used interior and edge portions of banks proportional to the abundance of their potential prey when sharks were absent but shifted to interior portions of banks to minimize encounters with tiger sharks as predation risk increased. Other shark prey, however, shift to edge microhabitats when shark densities increase to take advantage of easier escape despite higher encounter rates with sharks.

The interaction of landscape features and escape ability likely is important in diverse communities.

When escape probabilities are high in habitats with high predator density, risk effects of predators can reverse the direction of commonly assumed indirect effects of top predators.

The interaction between landscape features and prey escape tactics can result in a single predator species having differential effects on their sympatric prey that could cascade through ecosystems and should be incorporated into a general framework for context dependence of risk effects.
Restoration and recovery from acidification in upland Welsh streams over 25 years
Authors: Ormerod S. J. , Durance Isabelle
Published: December 2008

Streams affected by acid deposition should now be recovering biologically, but long‐term assessments are scarce. Here, we use the experimental catchments at Llyn Brianne (Wales, UK) to evaluate trends over 25 years (1981–2005) in the chemistry and macroinvertebrates of acid moorland and forest streams restored by liming relative to those responding ‘naturally’ to reduced deposition.

Mean H+ concentrations in acid moorland streams fell by c. 15–16 µquiv L−1 over the study, increasing mean winter pH by 0·8–1·3 units to pH 5·6–6·1. Liming moorland streams in 1987 and 1988 increased mean pH to 5·5–6·4, but differences from naturally recovering streams diminished over 12–18 years.

In limed and acid moorland streams, changes in invertebrate composition were consistent with recovery, and near‐identical. Four acid‐sensitive species, from a local pool of 29, increased significantly in abundance or occurrence, but effects were too small to increase similarity with circumneutral reference streams.

Mean H+ in acid forest streams declined by 8–15 µequiv L−1, but mean winter pH increased by only 0·4 units and remained too acid for invertebrate recovery (mean pH 4·8–5·2; Al > 0·3–0·6 mg L−1). One forest stream limed in 1987 and 1988 remained at mean pH > 5·9 thereafter, but there was no invertebrate response.

Climate affected recovery pattern. After accounting for time trends, wet winters increased acidity in moorland and forest streams sufficiently to offset 21–41% of the total 25‐year decrease in H+ concentration.

Synthesis and applications. These data from one of the world's longest running experiments on acidification confirm that upland British streams are recovering, but ecological effects are marginal and vary with land use. Conifer forest streams at Llyn Brianne remain too acid for sensitive invertebrates, while moorland streams are still at risk from acid events. In this example, liming had few long‐term benefits compared with natural recovery, and we suggest that this should be a key, general criterion in evaluating the outcomes of ecological restoration.
Why does Dasineura dielsi‐induced galling of Acacia cyclops not impede vegetative growth?
Authors: Moseley C. T. , Cramer M. D. , Kleinjan C. A. , Hoffmann J. H.
Published: December 2008

Conventionally, agent host specificity has been the major concern in the selection of prospective agents for biological control of weeds. However, subtle interactions between agent and host plant that could influence the outcome of the biological control programme also need to be identified and assessed when selecting potential agents.

A gall‐forming cecidomyiid Dasineura dielsi was introduced into South Africa for biological control of an invasive tree species, Acacia cyclops. Galls of D. dielsi form on flowers and prevent seed production, the intended aim of the biological control programme. Possible indirect effects of gall induction on vegetative growth of A. cyclops were investigated.

The carbon costs of producing and maintaining galls and pods were compared by measuring their gas exchange characteristics, and those of subtending phyllodes. Relocation of 14C from phyllodes to galls and pods, and nutrient composition of galls and pods, were compared. Insecticide was used to exclude D. dielsi from trees, enabling comparison of growth rates of predominantly gall‐bearing and predominantly podded branches.

Removal of galls, but not of pods, elevated photosynthetic rates of subtending phyllodes, indicating greater photosynthate demand by galls than pods. In light, the photosynthetic rates of expanded pods exceeded respiration rates. In contrast, there was a net release of CO2 from all age classes of galls in both light and dark. 14C allocation to mature galls was approximately three times as high as it was to young galls or immature pods.

Pod production required more mineral nutrient than gall production, with N, P and Ca contents of mature pods (including seeds) being nine‐fold those of mature galls.

Increases in stem diameters (i.e. vegetative growth rates) were similar for predominantly gall and predominantly pod bearing trees.

Synthesis and applications. Although nutrient costs were lower for galls than pods, this advantage was offset by higher carbon costs of gall production and the influence on plant growth was neutral. These findings illustrate that subtle physiological effects of herbivorous insects may influence the ecology of their hosts and should be considered during screening of potential agents for biological control.
Genetic correlates of protection against HIV infection: the ally within
Authors: Piacentini L. , Biasin M. , Fenizia C. , Clerici M.
Published: December 2008

Repeated exposure to HIV does not necessarily result in infection and HIV infection does not inevitably lead to the development of the AIDS. Multiple immunological and genetic features can confer resistance to HIV acquisition and progression at different steps in viral infection; a full understanding of these mechanisms could result in the development of novel therapeutic and vaccine approaches for HIV infection. In this review, we focus on the genetic mechanisms associated with resistance to HIV infection and to the progression to AIDS.
Immune dysregulation in human immunodeficiency virus infection: know it, fix it, prevent it?
Authors: Boasso A. , Shearer G. M. , Chougnet C.
Published: December 2008

Infection of humans by the human immunodeficiency virus (HIV) causes a progressive, multifactorial impairment of the immune system eventually leading to the acquired immunodeficiency syndrome (AIDS). No cure or vaccine exists yet against HIV infection. More worrisome is the fact that despite having identified HIV as the cause of the AIDS, we still do not understand what pathogenic mechanisms lead to the debacle of the immune system. In this review we consider the extent and the limits of our knowledge of HIV pathogenesis, and how this knowledge may be used to design preventive and therapeutic approaches.
Are QST–FST comparisons for natural populations meaningful?
Authors: PUJOL B. , WILSON A. J. , ROSS R. I. C. , PANNELL J. R.
Published: December 2008

Comparisons between putatively neutral genetic differentiation amongst populations, FST, and quantitative genetic variation, QST, are increasingly being used to test for natural selection. However, we find that approximately half of the comparisons that use only data from wild populations confound phenotypic and genetic variation. We urge the use of a clear distinction between narrow‐sense QST, which can be meaningfully compared with FST, and phenotypic divergence measured between populations, PST, which is inadequate for comparisons in the wild. We also point out that an unbiased estimate of QST can be found using the so‐called ‘animal model’ of quantitative genetics.
Can clone size serve as a proxy for clone age?An exploration using microsatellite divergence in Populus tremuloides
Authors: ALLY D. , RITLAND K. , OTTO S. P.
Published: December 2008

In long‐lived clonal plants, the overall size of a clone is often used to estimate clone age. The size of a clone, however, might be largely determined by physical or biotic interactions, obscuring the relationship between clone size and age. Here, we use the accumulation of mutations at 14 microsatellite loci to estimate clone age in trembling aspen (Populus tremuloides) from southwestern Canada. We show that the observed patterns of genetic divergence are consistent with a model of increasing ramet population size, allowing us to use pairwise genetic divergence as an estimator of clone age. In the populations studied, clone size did not exhibit a significant relationship with microsatellite divergence, indicating that clone size is not a good proxy for clone age. In P. tremuloides, the per‐locus per‐year neutral somatic mutation rate across 14 microsatellite loci was estimated to lie between 6 × 10−7 (lower bound) and 4 × 10−5 (upper bound).
Somatic mutations as a useful tool for studying clonal dynamics in trees
Authors: HEINZE BERTHOLD , FUSSI BARBARA
Published: December 2008

The seemingly eternal cycles of clonal growth in many tree species, with members of Populus (aspen, poplars, cottonwoods and the like) featuring most prominently, provoke a number of questions on the interface between ecology, genetics and forestry. In this issue, two groups present their approaches to clonal dynamics (Ally et al. 2008 and Mock et al. 2008), using microsatellite (or simple sequence repeat, SSR) variation in P. tremuloides. Ally et al. developed and applied a model for using microsatellites to estimate clone age and infer other community characteristics. Mock et al. used fewer microsatellites but in more individuals, to examine clone size and distribution across the landscape.
The evolution of sexual and parthenogeneticWarramaba: a window onto Plio–Pleistocene diversification processes in an arid biome
Authors: KEARNEY MICHAEL , BLACKET MARK J.
Published: December 2008

Environmental changes over the Plio‐Pleistocene have been key drivers of speciation patterns and genetic diversification in high‐latitude and mesic environments, yet comparatively little is known about the evolutionary history of species in arid environments. We applied phylogenetic and phylogeographic analyses to understand the evolutionary history ofWarramabagrasshoppers from the Australian arid zone, a group including sexual and parthenogenetic lineages. Sequence data (mitochondrial COI) showed that the four major sexual lineages withinWarramabamost likely diverged in the Pliocene, around 2–7 million years ago. All sexual lineages exhibited considerable phylogenetic structure. Detailed analyses of the hybrid parthenogenetic speciesW. virgoand its sexual progenitors showed a pattern of high phylogenetic diversity and phylogeographic structure in northern lineages, and low diversity and evidence for recent expansion in southern lineages. Northern sexual lineages persisted in localized refugia over the Pleistocene, with sustained barriers promoting divergence over this period. Southern parts of the present range became periodically unsuitable during the Pleistocene, and it is into this region that parthenogenetic lineages have expanded. Our results strongly parallel those for sexual and parthenogenetic lineages of the geckoHeteronotiafrom the same region, indicating a highly general effect of Plio‐Pleistocene environmental change on diversification processes in arid Australia.
Sea‐level changes and palaeo‐ranges: reconstruction of ancient shorelines and river drainages and the phylogeography of the Australian land crayfishEngaeus sericatusClark (Decapoda: Parastacidae)
Authors: SCHULTZ MARK B. , IERODIACONOU DANIEL A. , SMITH SARAH A. , HORWITZ PIERRE , RICHARDSON ALASTAIR M. M. , CRANDALL KEITH A. , AUSTIN CHRISTOPHER M.
Published: December 2008

Historical sea levels have been influential in shaping the phylogeography of freshwater‐limited taxa via palaeodrainage and palaeoshoreline connections. In this study, we demonstrate an approach to phylogeographic analysis incorporating historical sea‐level information in a nested clade phylogeographic analysis (NCPA) framework, using burrowing freshwater crayfish as the model organism. Our study area focuses on the Bass Strait region of southeastern Australia, which is marine region encompassing a shallow seabed that has emerged as a land bridge during glacial cycles connecting mainland Australia and Tasmania. Bathymetric data were analysed using Geographical Information Systems (GIS) to delineate a palaeodrainage model when the palaeocoastline was 150 m below present‐day sea level. Such sea levels occurred at least twice in the past 500 000 years, perhaps more often or of larger magnitude within the last 10 million years, linking Victoria and Tasmania. Inter‐locality distance measures confined to the palaeodrainage network were incorporated into an NCPA of crayfish (Engaeus sericatusClark 1936) mitochondrial 16S rDNA haplotypes. The results were then compared to NCPAs using present‐day river drainages and traditional great‐circle distance measures. NCPA inferences were cross‐examined using frequentist and Bayesian procedures in the context of geomorphological and historical sea‐level data. We found distribution of present‐day genetic variation inE. sericatusto be partly explained not only by connectivity through palaeodrainages but also via present‐day drainages or overland (great circle) routes. We recommend that future studies consider all three of these distance measures, especially for studies of coastally distributed species.