bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of the α1L‐adrenoceptor in rat cerebral cortex and possible relationship between α1L‐ and α1A‐adrenoceptors
Authors: Morishima S , Suzuki F , Yoshiki H , Md Anisuzzaman A S , Sathi Z S , Tanaka T , Muramatsu I 
Published: January 2008

Background and purpose:In addition to α1A, α1Band α1D‐adrenoceptors (ARs), putative α1L‐ARs with a low affinity for prazosin have been proposed. The purpose of the present study was to identify the α1A‐AR and clarify its pharmacological profile using a radioligand binding assay.Experimental approach:Binding experiments with [3H]‐silodosin and [3H]‐prazosin were performed in intact tissue segments and crude membrane preparations of rat cerebral cortex. Intact tissue binding assays were also conducted in rat tail artery.Key results:[3H]‐silodosin at subnanomolar concentrations specifically bound to intact tissue segments and membrane preparations of rat cerebral cortex at the same density (approximately 150 fmol mg−1total tissue protein). The binding sites in intact segments consisted of α1Aand α1L‐ARs that had different affinities for prazosin, while the binding sites in membranes showed an α1A‐AR‐like profile having single high affinity for prazosin. [3H]‐prazosin also bound at subnanomolar concentrations to α1Aand α1B‐ARs but not α1L‐ARs in cerebral cortex; the binding densities being approximately 200 and 290 fmol mg−1protein in the segments and the membranes, respectively. In the segments of tail artery, [3H]‐silodosin only recognized α1A‐ARs, whereas [3H]‐prazosin bound to α1Aand α1B‐ARs.Conclusions and implications:The present study clearly reveals the presence of α1L‐ARs as a pharmacologically distinct entity from α1Aand α1B‐ARs in intact tissue segments of rat cerebral cortex but not tail artery. However, the α1L‐ARs disappeared after tissue homogenization, suggesting their decomposition and/or their pharmacological profile changes to that of α1A‐ARs.British Journal of Pharmacology(2008)153, 1485–1494; doi:10.1038/sj.bjp.0707679; published online 28 January 2008
Acculturation and adaptation of immigrant adolescents in Greek urban schools
Authors: Motti‐Stefanidi Frosso , Pavlopoulos Vassilis , Obradović Jelena , Masten Ann S. 
Published: January 2008

The purpose of this study was to examine the acculturation, psychological well‐being, and school adjustment of Pontian adolescents from the former Soviet Union (FSU‐Pontians), who are immigrants of the diaspora living in Greece, compared with an immigrant group from Albania and native Greek classmates. The sample included 165 FSU‐Pontian immigrants, 272 immigrants from Albania, and their 525 Greek classmates (mean age = 13.7 years). School adjustment data were obtained using multiple methods and informants. Students also reported their subjective well‐being and acculturation via multiple measures. Findings indicated that FSU‐Pontian adolescents, although they are Greek citizens, had a stronger ethnic and a lower host‐national orientation than did Albanian students. Both immigrant groups experienced similar difficulties in school adjustment. Involvement in Greek culture was a salient predictor of school adjustment, while involvement in one's ethnic culture was related to subjective well‐being. Findings suggest that the acculturation expectations of host country members may be related to immigrants' acculturation orientations.
Mappings with integrable dilatation in higher dimensions
Authors: Manfredi Juan J. , Villamor Enrique 
Published: January 2008

Let

F
∈

W

loc

1
,
n

(
Ω
;

R

n

)

{F \in W_{{\text {loc}}}^{1,n}(\Omega ;{\mathbb {R}^n})}

be a mapping with nonnegative Jacobian

J
F

(
x
)
=
det
D
F
(
x
)
≥
0

{{J_F}(x) = \det DF(x) \geq 0}

for a.e. x in a domain

Ω
⊂

R

n

{\Omega \subset {\mathbb {R}^n}}

. The dilatation of F is defined (almost everywhere in

Ω

{\Omega }

) by the formula
\[

K
(
x
)
=

|

D
F
(
x
)

|

n

J
F

(
x
)

.

K(x) = \frac {{|DF(x){|^n}}}{{{J_F}(x)}}.

\]
Iwaniec and Šverák [IS] have conjectured that if

p
≥
n
−
1

{p \geq n - 1}

and

K
∈

L

l
o
c

p

(
Ω
)

{K \in L_{loc}^p(\Omega )}

then F must be continuous, discrete and open. Moreover, they have confirmed this conjecture in the two-dimensional case n = 2. In this article, we verify it in the higher-dimensional case

n
≥
2

{n \geq 2}

whenever

p
>
n
−
1

{p > n - 1}

.
Functional site profiling and electrostatic analysis of cysteines modifiable to cysteine sulfenic acid
Authors: Salsbury Freddie R. , Knutson Stacy T. , Poole Leslie B. , Fetrow Jacquelyn S. 
Published: January 2008

AbstractCysteine sulfenic acid (Cys‐SOH), a reversible modification, is a catalytic intermediate at enzyme active sites, a sensor for oxidative stress, a regulator of some transcription factors, and a redox‐signaling intermediate. This post‐translational modification is not random: specific features near the cysteine control its reactivity. To identify features responsible for the propensity of cysteines to be modified to sulfenic acid, a list of 47 proteins (containing 49 known Cys‐SOH sites) was compiled. Modifiable cysteines are found in proteins from most structural classes and many functional classes, but have no propensity for any one type of protein secondary structure. To identify features affecting cysteine reactivity, these sites were analyzed using both functional site profiling and electrostatic analysis. Overall, the solvent exposure of modifiable cysteines is not different from the average cysteine. The combined sequence, structure, and electrostatic approaches reveal mechanistic determinants not obvious from overall sequence comparison, including: (1) pKas of some modifiable cysteines are affected by backbone features only; (2) charged residues are underrepresented in the structure near modifiable sites; (3) threonine and other polar residues can exert a large influence on the cysteine pKa; and (4) hydrogen bonding patterns are suggested to be important. This compilation of Cys‐SOH modification sites and their features provides a quantitative assessment of previous observations and a basis for further analysis and prediction of these sites. Agreement with known experimental data indicates the utility of this combined approach for identifying mechanistic determinants at protein functional sites.
Not all ALMT1‐type transporters mediate aluminum‐activated organic acid responses: the case of ZmALMT1 – an anion‐selective transporter
Authors: Piñeros Miguel A. , Cançado Geraldo M. A. , Maron Lyza G. , Lyi Sangbom M. , Menossi Marcelo , Kochian Leon V. 
Published: January 2008

SummaryThe phytotoxic effects of aluminum (Al) on root systems of crop plants constitute a major agricultural problem in many areas of the world. Root exudation of Al‐chelating molecules such as low‐molecular‐weight organic acids has been shown to be an important mechanism of plant Al tolerance/resistance. Differences observed in the physiology and electrophysiology of root function for two maize genotypes with contrasting Al tolerance revealed an association between rates of Al‐activated root organic acid release and Al tolerance. Using these genotypes, we cloned ZmALMT1, a maize gene homologous to the wheat ALMT1 and Arabidopsis AtALMT1 genes that have recently been described as encoding functional, Al‐activated transporters that play a role in tolerance by mediating Al‐activated organic acid exudation in roots. The ZmALMT1 cDNA encodes a 451 amino acid protein containing six transmembrane helices. Transient expression of a ZmALMT1::GFP chimera confirmed that the protein is targeted to the plant cell plasma membrane. We addressed whether ZmALMT1 might underlie the Al‐resistance response (i.e. Al‐activated citrate exudation) observed in the roots of the Al‐tolerant genotype. The physiological, gene expression and functional data from this study confirm that ZmALMT1 is a plasma membrane transporter that is capable of mediating elective anion efflux and influx. However, gene expression data as well as biophysical transport characteristics obtained from Xenopus oocytes expressing ZmALMT1 indicate that this transporter is implicated in the selective transport of anions involved in mineral nutrition and ion homeostasis processes, rather than mediating a specific Al‐activated citrate exudation response at the rhizosphere of maize roots.
Arabidopsis eIF3e is regulated by the COP9 signalosome and has an impact on development and protein translation
Authors: Yahalom Avital , Kim Tae‐Houn , Roy Bijoyita , Singer Ruth , Von Arnim Albrecht G. , Chamovitz Daniel A. 
Published: January 2008

SummaryThe roles of individual eukaryotic translation initiation factor 3 (eIF3) subunits are largely unclear, although some are essential, while others are thought to have regulatory roles. The ‘e’ subunit, also known as Int‐6/Int6, is a candidate for a regulatory subunit as it is not essential for translation initiation in yeasts. eIF3e associates with the COP9 signalosome, and localizes to the nucleus in certain tissues. To further elucidate the roles of eIF3e, we have taken a genetic approach using Arabidopsis as a model system. Overexpression of eIF3e results in defects similar to mutations in the COP9 signalosome. eIF3e protein, but not transcript, over accumulates in csn mutants, and eIF3e is degraded in a proteasome‐dependent fashion. In vitro and in vivo assays suggest that excess eIF3e inhibits translation. We conclude that the COP9 signalosome maintains a precise regulation of eIF3e levels, which is necessary for normal development in Arabidopsis.
Metabolic changes detected by proton magnetic resonance spectroscopy in vivo and in vitro in a murin model of Parkinson’s disease, the MPTP‐intoxicated mouse
Authors: Chassain Carine , Bielicki Guy , Durand Elodie , Lolignier Stéphane , Essafi Fatma , Traoré Amidou , Durif Franck 
Published: January 2008

AbstractParkinson’s disease is a neurodegenerative disorder characterized by the progressive loss of the dopaminergic neurons in the substantia nigra pars compacta, which project to the striatum. The aim of this study was to analyze in vivo and in vitro consequences of dopamine depletion on amount of metabolites in a mouse model of Parkinson’s disease using proton 1H magnetic resonance spectroscopy (MRS). The study was performed on control mice (n = 7) and MPTP‐intoxicated mice (n = 7). All the experiments were performed at 9.4 T. For in vivo MRS acquisitions, mice were anesthetized and carefully placed on an animal handling system with the head centered in birdcage coil used for both excitation and signal reception. Spectra were acquired in a voxel (8 μL) centered in the striatum, applying a point‐resolved spectroscopy sequence (TR = 4000 ms, TE = 8.8 ms). After in vivo MRS acquisitions, mice were killed; successful lesion verified by tyrosine hydroxylase immunolabeling on the substantia nigra pars compacta and in vitro MRS acquisitions performed on perchloric extracts of anterior part of mice brains. In vitro spectra were acquired using a standard one‐pulse experiment. The absolute concentrations of metabolites were determined using jmrui (Lyon, France) from 1H spectra obtained in vivo on striatum and in vitro on perchloric extracts. Glutamate (Glu), glutamine (Gln), and GABA concentrations obtained in vivo were significantly increased in striatum of MPTP‐lesioned mice (Glu: 15.5 ± 2.5 vs. 12.9 ± 1.0 mmol/L, p < 0.05; Gln: 2.3 ± 0.9 vs. 1.8 ± 0.6 mmol/L, p < 0.05; GABA: 2.3 ± 0.9 vs. 1.3 ± 0.6 mmol/L, p < 0.05). The in vitro results confirmed these results, Glu (10.9 ± 2.5 vs. 7.9 ± 1.7 μmol/g, p < 0.05), Gln (6.8 ± 2.9 vs. 4.3 ± 1.0 μmol/g, p < 0.05), and GABA (2.9 ± 0.9 vs. 1.5 ± 0.4 μmol/g, p < 0.01). The present study strongly supports a hyperactivity of the glutamatergic cortico‐striatal pathway hypothesis after dopaminergic denervation in association with an increase of striatal GABA levels. It further shows an increased of striatal Gln concentrations, perhaps as a strategy to protect neurons from Glu excitotoxic injury after striatal dopamine depletion.
NMDA receptor‐mediated excitotoxic neuronal apoptosis in vitro and in vivo occurs in an ER stress and PUMA independent manner
Authors: Concannon Caoimhín G. , Ward Manus W. , Bonner Helena P. , Kuroki Katsura , Tuffy Liam P. , Bonner Caroline T. , Woods Ina , Engel Tobias , Henshall David C. , Prehn Jochen H. M. 
Published: January 2008

AbstractDisruption of endoplasmic reticulum (ER) Ca2+ homeostasis and ER dysfunction have been suggested to contribute to excitotoxic and ischaemic neuronal injury. Previously, we have characterized the neural transcriptome following ER stress and identified the BH3‐only protein, p53 up‐regulated mediator of apoptosis (PUMA), as a central mediator of ER stress toxicity. In this study, we investigated the effects of excitotoxic injury on ER Ca2+ levels and induction of ER stress responses in models of glutamate‐ and NMDA‐induced excitotoxic apoptosis. While exposure to the ER stressor tunicamycin induced an ER stress response in cerebellar granule neurons, transcriptional activation of targets of the ER stress response, including PUMA, were absent following glutamate‐induced apoptosis. Confocal imaging revealed no long‐term changes in the ER Ca2+ level in response to glutamate. Murine cortical neurons and organotypic hippocampal slice cultures from PUMA+/+ and PUMA−/− animals provided no evidence of ER stress and did not differ in their sensitivity to NMDA. Finally, NMDA‐induced excitotoxic apoptosis in vivo was not associated with ER stress, nor did deficiency in PUMA alleviate the injury induced. Our data suggest that NMDA receptor‐mediated excitotoxic apoptosis occurs in vitro and in vivo in an ER stress and PUMA independent manner.
Seawater Mg/Ca controls polymorph mineralogy of microbial CaCO3: A potential proxy for calcite‐aragonite seas in Precambrian time
Authors: RIES J. B. , ANDERSON M. A. , HILL R. T. 
Published: January 2008

ABSTRACTA previously published hydrothermal brine‐river water mixing model driven by ocean crust production suggests that the molar Mg/Ca ratio of seawater (mMg/Casw) has varied significantly (~1.0–5.2) over Precambrian time, resulting in six intervals of aragonite‐favouring seas (mMg/Casw > 2) and five intervals of calcite‐favouring seas (mMg/Casw < 2) since the Late Archaean. To evaluate the viability of microbial carbonates as mineralogical proxy for Precambrian calcite‐aragonite seas, calcifying microbial marine biofilms were cultured in experimental seawaters formulated over the range of Mg/Ca ratios believed to have characterized Precambrian seawater. Biofilms cultured in experimental aragonite seawater (mMg/Casw = 5.2) precipitated primarily aragonite with lesser amounts of high‐Mg calcite (mMg/Cacalcite = 0.16), while biofilms cultured in experimental calcite seawater (mMg/Casw = 1.5) precipitated exclusively lower magnesian calcite (mMg/Cacalcite = 0.06). Furthermore, Mg/Cacalcite varied proportionally with Mg/Casw. This nearly abiotic mineralogical response of the biofilm CaCO3 to altered Mg/Casw is consistent with the assertion that biofilm calcification proceeds more through the elevation of , via metabolic removal of CO2 and/or H+, than through the elevation of Ca2+, which would alter the Mg/Ca ratio of the biofilm's calcifying fluid causing its pattern of CaCO3 polymorph precipitation (aragonite vs. calcite; Mg‐incorporation in calcite) to deviate from that of abiotic calcification. If previous assertions are correct that the physicochemical properties of Precambrian seawater were such that Mg/Casw was the primary variable influencing CaCO3 polymorph mineralogy, then the observed response of the biofilms’ CaCO3 polymorph mineralogy to variations in Mg/Casw, combined with the ubiquity of such microbial carbonates in Precambrian strata, suggests that the original polymorph mineralogy and Mg/Cacalcite of well‐preserved microbial carbonates may be an archive of calcite‐aragonite seas throughout Precambrian time. These results invite a systematic evaluation of microbial carbonate primary mineralogy to empirically constrain Precambrian seawater Mg/Ca.
Carbon pools and isotopic trends in a hypersaline cyanobacterial mat
Authors: WIELAND A. , PAPE T. , MÖBIUS J. , KLOCK J.–H. , MICHAELIS W. 
Published: January 2008

ABSTRACTThe fine‐scale depth distribution of major carbon pools and their stable carbon isotopic signatures (δ13C) were determined in a cyanobacterial mat (Salin‐de‐Giraud, Camargue, France) to study early diagenetic alterations and the carbon preservation potential in hypersaline mat ecosystems. Particular emphasis was placed on the geochemical role of extracellular polymeric substances (EPS). Total carbon (Ctot), organic carbon (Corg), total nitrogen (Ntot), total hydrolysable amino acids (THAA), carbohydrates, cyanobacteria‐derived hydrocarbons (8‐methylhexadecane, n‐heptadec‐5‐ene, n‐heptadecane) and EPS showed highest concentrations in the top millimetre of the mat and decreased with depth. The hydrocarbons attributed to cyanobacteria showed the strongest decrease in concentration with depth. This correlated well with the depth profiles of oxygenic photosynthesis and oxygen, which were detected in the top 0.6 and 1.05 mm, respectively, at a high down‐welling irradiance (1441 µmol photons m−2 s−1). At depths beneath the surface layer, the Corg was composed mainly of amino acids and carbohydrates. A resistance towards microbial degradation could have resulted from interactions with diverse functional groups present in biopolymers (EPS) and with minerals deposited in the mat. A 13C enrichment with depth for the total carbon pool (Ctot) was observed, with δ13C values ranging from –16.3‰ at the surface to –11.3‰ at 9–10 mm depth. Total lipids depicted a δ13C value of –17.2‰ in the top millimetre and then became depleted in 13C with depth (–21.7 to –23.3‰). The δ13C value of EPS varied only slightly with depth (–16.1 to –17.3‰) and closely followed the δ13C value of Corg at depths beneath 4 mm. The EPS represents an organic carbon pool of preservation potential during early stages of diagenesis in recent cyanobacterial mats as a result of a variety of possible interactions. Their analyses might improve our understanding of fossilized microbial remains from mat ecosystems.
Fossilized microorganisms associated with zeolite–carbonate interfaces in sub‐seafloor hydrothermal environments
Authors: IVARSSON M. , LINDBLOM S. , BROMAN C. , HOLM N. G. 
Published: January 2008

ABSTRACTIn this paper we describe carbon‐rich filamentous structures observed in association with the zeolite mineral phillipsite from sub‐seafloor samples drilled and collected during the Ocean Drilling Program (ODP) Leg 197 at the Emperor Seamounts. The filamentous structures are ~5 µm thick and ~100–200 µm in length. They are found attached to phillipsite surfaces in veins and entombed in vein‐filling carbonates. The carbon content of the filaments ranges between ~10 wt% C and 55 wt% C. They further bind to propidium iodide (PI), which is a dye that binds to damaged cell membranes and remnants of DNA.Carbon‐rich globular microstructures, 1–2 µm in diameter, are also found associated with the phillipsite surfaces as well as within wedge‐shaped cavities in phillipsite assemblages. The globules have a carbon content that range between ~5 wt% C and 55 wt% C and they bind to PI. Ordinary globular iron oxides found throughout the samples differ in that they contain no carbon and do not bind to the dye PI. The carbon‐rich globules are mostly concentrated to a film‐like structure that is attached to the phillipsite surfaces. This film has a carbon content that ranges between ~25 wt% C and 75 wt% C and partially binds to PI. EDS analyses show that the carbon in all structures described are not associated with calcium and therefore not bound in carbonates. The carbon content and the binding to PI may indicate that the filamentous structures could represent fossilized filamentous microorganisms, the globules could represent fossilized microbial cells and the film‐like structures could represent a microbially produced biofilm.Our results extend the knowledge of possible habitable niches for a deep biosphere in sub‐seafloor environments and suggests, as phillipsite is one of the most common zeolite mineral in volcanic rocks of the oceanic crust, that it could be a common feature in the oceanic crust elsewhere.
Earliest fossil record of bacterial–cyanobacterial mat consortia: the early Silurian Passage Creek biota (440 Ma, Virginia, USA)
Authors: TOMESCU A. M. F. , HONEGGER R. , ROTHWELL G. W. 
Published: January 2008

ABSTRACTCyanobacteria in terrestrial and aquatic habitats are frequently associated with heterotrophic bacteria, and such associations are most often metabolically interactive. Functionally, the members of such bacterial–cyanobacterial consortia benefit from diverse metabolic capabilities of their associates, thus exceeding the sum of their parts. Such associations may have been just as ubiquitous in the past, but the fossil record has not produced any direct evidence for such associations to date. In this paper, we document fossil bacteria associated with a macrophytic cyanobacterial mat in the early Silurian (Llandovery) Massanutten Sandstone of Virginia, USA. Both the bacterial and the cyanobacterial cells are preserved by mineral replacement (pyrite subsequently replaced by iron oxyhydroxides) within an amorphous carbonaceous matrix which represents the common exopolysaccharide investment of the cyanobacterial colony. The bacteria are rod‐shaped, over 370 nm long and 100 nm in diameter, and occur both as isolated cells and as short filaments. This occurrence represents the oldest fossil evidence for bacterial–cyanobacterial associations, documenting that such consortia were present 440 Ma ago, and revealing the potential for them to be recognized deeper in the fossil record.
Prevalence of nonspecific low back pain in schoolchildren aged between 13 and 15 years
Authors: Masiero Stefano , Carraro Elena , Celia Andrea , Sarto Diego , Ermani Mario 
Published: January 2008

AbstractAim: To investigate the annual (2005) prevalence of nonspecific low back pain (LBP), defined as lumbago not attributed to recognizable, known specific pathology, in a population of adolescents.Methods: We investigated 7542 school teenagers with a structured questionnaire consisting of demographic and anthropometric items, psychosocial factors and life style, presence and intensity of LBP, family history of LBP, and questions about whether the teenager had been referred to a physician for this problem. Univariate (t‐test, Mann–Whitney U‐test and chi‐square test) and multivariate analyses (logistic regression) were performed.Results: A total of 1180 (20.5%) teenagers reported one or more episodes of LBP, of whom 900 (76.3%) had consulted a health provider. A significantly greater percentage of LBP was found in the students who practised aerobics and swimming compared to the other sports. The search for risk factors in the whole population revealed no associations between LBP and the investigated anthropometrics or lifestyle items, whereas a significant association was found for gender (to be female), positive family history of LBP and absence of sports activity.Conclusions: Our study shows that nonspecific LBP is a frequent event in teenagers, particularly in females, sedentary children and those with a family history of LBP.