bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure and histochemistry of the stigmatic and transmitting tissues of Rodriguezia venusta (Orchidaceae) during flower development
Authors: Leitão Carlos André E. , Cortelazzo Angelo L.
Published: May 2010

Stigma and transmitting tissue are floral structures essential for sexual reproduction of angiosperms and can be useful features in taxonomic studies. Rodriguezia venusta (Lindl.) Rchb. f. is an epiphytic orchid belonging to the large subfamily Epidendroideae. The present study describes the structure and histochemistry of the stigmatic and transmitting tissues of R. venusta during flower development. The differentiation and the secretory activity of the stigmatic and transmitting tissues are already visible in the initial stages of development of the flower bud studied. These tissues, which have a reticulated appearance, predominantly secrete mucilaginous material that is accumulated in the intercellular spaces. The stigma is covered by a cuticle that extends over the internal surface of the central canal in the transmitting tissue in this apical portion. In the stigma, the cuticle appears to have micropores, and in the intercellular spaces, there are small spherical bodies that stain for lipids, proteins and total carbohydrates. The functions of these bodies still remain unknown.
Effects of fire, post-fire defoliation, drought and season on regrowth and carbohydrate reserves of alpine snowgrass Poa fawcettiae (Poaceae)
Authors: Tolsma A. D. , Tolhurst K. G. , Read S. M.
Published: May 2010

Following defoliation, grasses regenerate foliage from basal buds. We used a combination of field, glasshouse and growth-room experiments to investigate the role of carbohydrate reserves in regrowth of Poa fawcettiae Vickery following fire or mock grazing, and the effect on reserve dynamics of post-fire defoliation, drought and seasonal factors. Fructan reserves of burnt plants were depleted during foliage regeneration, and remained below those of unburnt plants for up to 10 months in the field, and for up to 3 months in the glasshouse. Plants were resilient to occasional mechanical clipping of foliage, but experienced significant depletion in fructan reserves and high tiller mortality when clipped at frequent intervals. Cold treatment led to fructan concentrations almost double those in plants growing at a warm temperature, explaining peak autumn levels in field plants, whereas a short drought treatment doubled the concentration of ethanol-soluble carbohydrates. Taken together, these data show how the dynamics of carbohydrate reserves, and specifically tiller-base fructan reserves, explain the vegetative regeneration capacity of P. fawcettiae.
Ontogenetic, anatomical and histochemical study of the extrafloral nectaries of Sapium biglandulosum (Euphorbiaceae)
Authors: Coutinho Ítalo Antônio Cotta , Valente Vânia Maria Moreira , Meira Renata Maria Strozi Alves
Published: May 2010

The present paper aims to confirm the nature of secretory structures found on the petiole and leaf margins of Sapium biglandulosum Müell. Arg. The anatomy, ontogenesis and histochemistry were studied by light microscopy, whereas mono- and disaccharides in the exudates were detected by high performance liquid chromatography. The exudate from the petiole had a total sugar concentration of 32.5% (w/v), of which 38.1% was fructose, 43.7% glucose and 18.2% sucrose. The petiolar gland started its development from a group of meristematic cells that underwent asynchronous divisions. At the end of the ontogenesis, a well structured vascularised gland made up of a palisade secretory epidermis, secretory parenchyma and a secretory pore was observed. Leaf-margin glands showed a similar anatomy. Histochemical tests revealed the presence of proteins, pectins, carbohydrates, tannins and anthocyanins. On the basis of our results, there is compelling evidence that the studied glands are in fact extrafloral nectaries.
Histology of organogenesis and somatic embryogenesis in excised root cultures of an endangered species Tylophora indica (Asclepiadaceae)
Authors: Sahai Aastha , Shahzad Anwar , Sharma Shiwali
Published: May 2010

This paper reports an efficient regeneration protocol through parallel organogenic and embryogenic pathways from green root segments (GRSs) of Tylophora indica (Burm.f) Merrill. GRSs explants from one year old in vitro cultures were cultured on Murashige and Skoog (MS) medium containing various cytokinins. Five µmol/L of 6-benzyladenine (BA) was most responsive for organogenesis in 1.5 cm long GRSs. Repeated subculture on medium containing both BA (5 µmol/L) and 1-naphthleneacetic acid (NAA) (0.1 µmol/L) promoted multiplication and proliferation of direct shoot buds (46.80 ± 0.96) and callus mediated somatic embryogenesis (18.07 ± 0.33). Germinated embryos isolated from callus were transferred onto maturation medium consisting of half-strength MS medium either devoid of plant growth regulators (PGRs) or with various concentrations of gibberellic acid (GA). Microshoots were excised during subculture and transferred onto root induction medium, thus ensuring a continuous supply of germplasm. Morphogenic variations were noticed in types of roots induced on various auxins. Regenerated plantlets and emblings hardened best on vermiculite with a survival rate of 90% and 70% respectively. However, the emblings were healthier in comparison to the regenerated plants. Histological analysis showed the origin and development of organogenesis.
Quantitative determination of ion distributions in bacterial lipopolysaccharide membranes by grazing-incidence X-ray fluorescence
Authors: Schneck Emanuel , Schubert Thomas , Konovalov Oleg V. , Quinn Bonnie E. , Gutsmann Thomas , Brandenburg Klaus , Oliveira Rafael G. , Pink David A. , Tanaka Motomu
Published: May 2010

A model of the outer membrane of Gram-negative bacteria was created by the deposition of a monolayer of purified rough mutant lipopolysaccharides at an air/water interface. The density profiles of monovalent (K
+
) and divalent (Ca
2+
) cations normal to the lipopolysaccharides (LPS) monolayers were investigated using grazing-incidence X-ray fluorescence. In the absence of Ca
2+
, a K
+
concentration peak was found in the negatively charged LPS headgroup region. With the addition of CaCl
2
, Ca
2+
ions almost completely displaced K
+
ions from the headgroup region. By integrating the experimentally reconstructed excess ion density profiles, we obtained an accurate measurement of the effective charge density of LPS monolayers. The experimental findings were compared to the results of Monte Carlo simulations based on a coarse-grained minimal model of LPS molecules and showed excellent agreement.
Chemotherapeutic drug susceptibility associated SNPs are enriched in expression quantitative trait loci
Authors: Gamazon Eric R. , Huang R. Stephanie , Cox Nancy J. , Dolan M. Eileen
Published: May 2010

Pharmacogenomics has employed candidate gene studies and, more recently, genome-wide association studies (GWAS) in efforts to identify loci associated with drug response and/or toxicity. The advantage of GWAS is the simultaneous, unbiased testing of millions of SNPs; the challenge is that functional information is absent for the vast majority of loci that are implicated. In the present study, we systematically evaluated SNPs associated with chemotherapeutic agent–induced cytotoxicity for six different anticancer agents and evaluated whether these SNPs were disproportionately likely to be within a functional class such as coding (consisting of missense, nonsense, or frameshift polymorphisms), noncoding (such as 3′UTRs or splice sites), or expression quantitative trait loci (eQTLs; indicating that a SNP genotype is associated with the transcript abundance level of a gene). We found that the chemotherapeutic drug susceptibility–associated SNPs are more likely to be eQTLs, and, in fact, more likely to be associated with the transcriptional expression level of multiple genes (
n
≥ 10) as potential master regulators, than a random set of SNPs in the genome, conditional on minor allele frequency. Furthermore, we observed that this enrichment compared with random expectation is not present for other traditionally important coding and noncoding SNP functional categories. This research therefore has significant implications as a general approach for the identification of genetic predictors of drug response and provides important insights into the likely function of SNPs identified in GWAS analysis of pharmacologic studies.
CHANGES AND CONTINUITIES IN MATERNITY POLICIES
Authors: Kennedy Patricia , Einasto Heili
Published: May 2010

This paper examines maternity policy legislation in Ireland and Estonia, focussing on changes and continuities. Throughout the paper we speak about maternity, referring to the physiological aspect of motherhood and the unique capacity of women to bear children. Very often maternity is not covered by a single policy, but it is an amalgam of various policy fields, like health, social security, and labour. These policies are all embedded in the legal framework which therefore presents a means to achieve the desired end in the society by marking the borders between the allowed and the prohibited. Even though these lines are not always followed, and may sometimes stay only on paper, they still have an impact on how the ideal state of things is perceived. They are linked to the principles upon which welfare is organised and in the case of Estonia and Ireland these have been very different. In the former, there has been the communist ideal of woman as worker and mother, and in Ireland can be seen the enduring view of woman as mother first, citizen worker second. In this paper we concentrate on the legislation since the 1920s, that is, since both countries became independent republics. We explore the critical junctures that have shaped the policy paths in both countries.
VOLUNTEERING AFTER RETIREMENT
Authors: Erlinghagen Marcel
Published: May 2010

In view of the steady growth in life expectancy in recent decades the question is increasingly being raised whether and how older people should be encouraged to be more active, and particularly to engage in unpaid voluntary work. Taking adult life as a whole the conditions for such charitable involvement would appear to be especially favourable after retirement. However, these analyses, which are based on German longitudinal data, show that the effect of entering retirement is often exaggerated. Rather, the individual's previous volunteering experiences are of major importance in his decision to take up and continue voluntary work in later life. At the same time the analyses show how important the major resources of health and education are, particularly for participation in voluntary work during ageing.
EXPLAINING PARTICIPATION IN UNDECLARED WORK
Authors: Williams Colin C. , Round John
Published: May 2010

This paper evaluates critically competing explanations for participation in undeclared work that either read engagement through a structuralist lens as driven by ‘exclusion’ from state benefits and the circuits of the modern economy or through a neo-liberal and/or post-structuralist lens as driven by the voluntary ‘exit’ of workers out of formal institutions. Reporting a 2005/6 household work practices survey involving 313 face-to-face interviews in contemporary Moscow, the finding is that there is no single unique logic underpinning undeclared work in this post-Soviet city; such work is neither universally driven by exclusion nor exit. Different mixtures of the two prevail across different populations and forms of undeclared work. The outcome is a call for greater appreciation of the multifarious character of undeclared work and a move beyond simplistic explanations and policy responses.
The Role of Attention in Binding Visual Features in Working Memory: Evidence from Cognitive Ageing
Authors: Brown Louise A. , Brockmole James R.
Published: May 2010

Two experiments were conducted to assess the costs of attentional load during a feature (colour–shape) binding task in younger and older adults. Experiment 1 showed that a demanding backwards counting task, which draws upon central executive/general attentional resources, reduced binding to a greater extent than individual feature memory, but the effect was no greater in older than in younger adults. Experiment 2 showed that presenting memory items sequentially rather than simultaneously, such that items are required to be maintained while new representations are created, selectively affects binding performance in both age groups. Although this experiment exhibited an age-related binding deficit overall, both age groups were affected by the attention manipulation to an equal extent. While a role for attentional processes in colour–shape binding was apparent across both experiments, manipulations of attention exerted equal effects in both age groups. We therefore conclude that age-related binding deficits neither emerge nor are exacerbated under conditions of high attentional load. Implications for theories of visual working memory and cognitive ageing are discussed.
Effects of Simple- and Complex-Place Contexts in the Multiple-Context Paradigm
Authors: Isarida Takeo , Isarida Toshiko K.
Published: May 2010

In four experiments, a total of 384 undergraduates incidentally learned a list of 24 nouns twice in the same context (same-context repetition) or different contexts (different-context repetition). Free recall was measured in a neutral context. Experiments 1, 2, and 3 used a context repetition (same- or different-context repetition) × inter-study and retention intervals (10 min or 1 day) between-participants design. Context was manipulated by the combination of place, social environment, and encoding task (Experiment 1), place and social environment (Experiment 2), or place alone (Experiment 3). Experiment 4 used a context repetition × type of context (context manipulated by place or by place, social environment, and encoding task) between-participants design, with a 10-min inter-study interval and a one-day retention interval. The present results indicate that the determinant of the superiority of same- or different-context repetition in recall is the type of context. Implications of the results were discussed.
Synthesis of TiO2 nanotube arrays and its application in mini-3D dye-sensitized solar cells
Authors: Liu Yong , Li Ming , Wang Hai , Zheng Jiemin , Xu Hongmei , Ye Qihong , Shen Hui
Published: May 2010

Here we report a mini-three-dimensional dye-sensitized solar cell (3D DSSC) based on TiO2 nanotube arrays (TNAs). TNAs were directly grown on spiral-shaped titanium wire via a facile potentiostatic anodization. Furthermore, the TNAs film was characterized by scanning electron microscopy, x-ray diffraction and transmission electron microscopy, indicating that the annealed TNAs were composed of single-crystalline anatase particles. Unlike conventional flat DSSC, this mini-3D DSSC could easily hold liquid electrolyte due to the capillary force which facilitated sealing the cell. This mini-3D DSSC showed an energy conversion efficiency of 4.1% under the AM 1.5 condition, which was much higher compared with that (3.2%) of the backside illuminated TNAs based DSSC of the same projected area.
Quantitative evaluation of probe response functions for Raman and fluorescence bands of single-crystalline and polycrystalline Al2O3
Authors: Wan K S , Tochino S , Zhu W L , Ohtsuka S , Pezzotti G
Published: May 2010

The probe response functions of Raman and fluorescence bands of single-crystalline sapphire and polycrystalline Al2O3 with different grain sizes were systematically evaluated and compared. As a general issue, it was found that the probe response function strongly depended on the selected signal and, more importantly, on grain size. From a comparison between the probe characteristics of Raman and fluorescence bands, the following characteristics could be found: (i) the probe depth of the Raman bands of sapphire single-crystal (the main band at 417 cm−1 was selected as a paradigm Raman sensor) was about a half that of the Cr3+ fluorescence doublet (a direct comparison was made with the R1 band located at 14 405 cm−1); (ii) the probe depth in polycrystalline Al2O3 decreased with decreasing grain size. In this latter case, the probe depth of the R1 band could be up to >10 times larger than that of the 417 cm−1 Raman band, the difference in depth increasing with decreasing grain size. These large differences in probe geometry need to be taken into consideration when applying spectroscopy methods as, for example, piezo-spectroscopic stress assessments. Nevertheless, the results of this investigation suggest that a noticeable improvement in the in-depth spatial resolution can be obtained using Raman rather than fluorescence bands as stress probes for assessing high property gradients present in the materials.
Temperature evolution in a magnetohydrodynamics simulation of a reversed-field pinch
Authors: Onofri M. , Malara F. , Veltri P.
Published: May 2010

The temperature evolution in a magnetohydrodynamics (MHD) simulation of a reversed-field pinch (RFP) is investigated including thermal conductivity. For numerical reasons, an isotropic thermal conductivity is used, even though in a RFP plasma the parallel conductivity is much larger than the perpendicular one so that magnetic field lines tend to become isothermal. The system shows alternating multiple helicity states and quasi-single helicity states. Single-helical-axis states are formed when the amplitude of the dominant mode is above a determined threshold, as observed in experiments. The relation between heat transport and magnetic field topology that is observed in RFP experiments cannot be found in the simulation, since thermal conductivity is independent of the magnetic field. This difficulty should be taken into account in the numerical investigation of the RFP dynamics. In this paper, the first description of the temperature evolution in a compressible MHD simulation of a RFP is given.
Stratification and coordinate systems for the moduli space of rational functions
Authors: Fujimura Masayo , Taniguchi Masahiko
Published: May 2010

In this note, we give a new simple system of global parameters on the moduli space of rational functions, and clarify the relation to the parameters indicating location of fixed points and the indices at them. As a byproduct, we solve a conjecture of Milnor affirmatively.
Immigration Reform: What Does It Mean for Agriculture and Rural America?
Authors: Martin Philip , Calvin Linda
Published: May 2010

Over half of the hired workers employed on U.S. crop farms have been unauthorized to work since the mid‐1990s, thereby increasing risk for employers if increased immigration law enforcement reduces the availability and raises the cost of farm labor. Immigration reform that legalizes farm workers could speed exits from the farm workforce, thus putting upward pressure on farm wages. Better enforcement of existing immigration laws would reduce the supply of farm workers, also putting upward pressure on wages. Producer response to higher wages depends, in part, on the availability of guest workers and alternatives to hand labor such as labor‐saving machinery.
Quality of Life in Adults Operated On for Hirschsprung Disease in Childhood
Authors: Gunnarsdóttir Anna , Sandblom Gabriel , Arnbjörnsson Einar , Larsson Lars‐Torsten
Published: May 2010

Objectives:

The aim of this study is to explore the long‐term quality of life (QoL) in adults after surgery for Hirschsprung disease in childhood.

Patients and Methods:

Altogether 51 patients were operated for HD at our center during the period 1969 to 1989. In 2007, the validated instruments for assessing QoL, the SF‐36 health survey and the Gastrointestinal Quality of Life Index (GIQLI), were sent to the 47 patients still alive at the time of the study. A retrospective review of the patient records was also done.

Results:

Forty‐two patients returned both questionnaires (89% response rate) at the median age of 28.5 (range 18–45) years. The median clinical follow‐up time was 5.7 years (range 5 months–23 years). At the last clinical control, 4 (9%) patients had a terminal enterostomy, 12 (29%) had soiling, 5 (12%) had constipation, and 2 (5%) experienced recurrent enterocolitis. In contrast to males, the subscores for females were lower for general health and mental health than for an age‐ and sex‐matched general population (P < 0.05). Patients having aganglionosis to the right colon had lower GIQLI scores than those with aganglionosis to the left colon (P < 0.05). In multivariate linear regression analysis, female sex was the only factor associated with lower GIQLI score (P < 0.05).

Conclusions:

The long‐term QoL of adults operated for Hirschsprung disease in their youth is satisfactory. Female scores were lower for general and mental health, compared with the matched control group. The study indicates that the longer the aganglionic segment, the greater its impact on QoL in later life.
Lack of Utility of Abdominal X‐rays in the Evaluation of Children With Constipation: Comparison of Different Scoring Methods
Authors: Pensabene Licia , Buonomo Carlo , Fishman Laurie , Chitkara Denesh , Nurko Samuel
Published: May 2010

Background and Aim:

Abdominal x‐rays are used diagnostically in the evaluation of children with constipation. However, their clinical utility has not been established. The aim of the study was to assess the accuracy of different methods in identifying children with functional constipation (FC) or nonretentive fecal incontinence (NRFI).

Patients and Methods:

Retrospective review of abdominal x‐rays in which colonic transit (CT), Barr, Leech, and fecal loading (FL) scores were blindly measured by blinded pediatric gastroenterologists and a radiologist. Children were classified a priori as FC or NRFI.

Results:

One hundred sixty patients (125 FC, 35 NRFI) were studied. There were significant differences (P < 0.05) when comparing those with FC and those with NRFI: CT: 51 ± 18 vs 40 ± 21 hours; Barr: 14 ± 5 vs 11 ± 4; Leech: 10 ± 2 vs 8 ± 2; FL: 2 ± 0.5 vs 1.7 ± 0.4. More than 20% of FC had normal Barr and Leech scores, whereas >50% of NRFI had abnormal scores. CT discriminated better between FC and NRFI. There was a significant correlation (P < 0.05) between CT and Barr (0.45), Leech (0.41) and FL scores (0.36), and between Barr and Leech scores (r = 0.94). There was good intraobserver correlation between Barr, Leech, and FL scores but poor interobserver reproducibility.

Conclusions:

Although significant differences in overall FC and NRFI scores exist, the discriminative value is low for all scores. There is poor interobserver reproducibility of the Barr, Leech, and FL scores. These findings confirm the limited value of the plain abdominal x‐ray in the evaluation of children with constipation.
Estrogen-mediated epigenetic repression of large chromosomal regions through DNA looping
Authors: Hsu Pei-Yin , Hsu Hang-Kai , Singer Gregory A.C. , Yan Pearlly S. , Rodriguez Benjamin A.T. , Liu Joseph C. , Weng Yu-I , Deatherage Daniel E. , Chen Zhong , Pereira Julia S. , Lopez Ricardo , Russo Jose , Wang Qianben , Lamartiniere Coral A. , Nephew Kenneth P. , Huang Tim H.-M.
Published: May 2010

The current concept of epigenetic repression is based on one repressor unit corresponding to one silent gene. This notion, however, cannot adequately explain concurrent silencing of multiple loci observed in large chromosome regions. The long-range epigenetic silencing (LRES) can be a frequent occurrence throughout the human genome. To comprehensively characterize the influence of estrogen signaling on LRES, we analyzed transcriptome, methylome, and estrogen receptor alpha (ESR1)-binding datasets from normal breast epithelia and breast cancer cells. This “omics” approach uncovered 11 large repressive zones (range, 0.35∼5.98 megabases), including a 14-gene cluster located on 16p11.2. In normal cells, estrogen signaling induced transient formation of multiple DNA loops in the 16p11.2 region by bringing 14 distant loci to focal ESR1-docking sites for coordinate repression. However, the plasticity of this free DNA movement was reduced in breast cancer cells. Together with the acquisition of DNA methylation and repressive chromatin modifications at the 16p11.2 loci, an inflexible DNA scaffold may be a novel determinant used by breast cancer cells to reinforce estrogen-mediated repression.
Binding Properties of the N-Acetylglucosamine and High-Mannose N-Glycan PP2-A1 Phloem Lectin in Arabidopsis
Authors: Beneteau Julie , Renard Denis , Marché Laurent , Douville Elise , Lavenant Laurence , Rahbé Yvan , Dupont Didier , Vilaine Françoise , Dinant Sylvie
Published: May 2010

Phloem Protein2 (PP2) is a component of the phloem protein bodies found in sieve elements. We describe here the lectin properties of the Arabidopsis (Arabidopsis thaliana) PP2-A1. Using a recombinant protein produced in Escherichia coli, we demonstrated binding to N-acetylglucosamine oligomers. Glycan array screening showed that PP2-A1 also bound to high-mannose N-glycans and 9-acyl-N-acetylneuraminic sialic acid. Fluorescence spectroscopy-based titration experiments revealed that PP2-A1 had two classes of binding site for N,N′,N″-triacetylchitotriose, a low-affinity site and a high-affinity site, promoting the formation of protein dimers. A search for structural similarities revealed that PP2-A1 aligned with the Cbm4 and Cbm22-2 carbohydrate-binding modules, leading to the prediction of a β-strand structure for its conserved domain. We investigated whether PP2-A1 interacted with phloem sap glycoproteins by first characterizing abundant Arabidopsis phloem sap proteins by liquid chromatography-tandem mass spectrometry. Then we demonstrated that PP2-A1 bound to several phloem sap proteins and that this binding was not completely abolished by glycosidase treatment. As many plant lectins have insecticidal activity, we also assessed the effect of PP2-A1 on weight gain and survival in aphids. Unlike other mannose-binding lectins, when added to an artificial diet, recombinant PP2-A1 had no insecticidal properties against Acyrthosiphon pisum and Myzus persicae. However, at mid-range concentrations, the protein affected weight gain in insect nymphs. These results indicate the presence in PP2-A1 of several carbohydrate-binding sites, with potentially different functions in the trafficking of endogenous proteins or in interactions with phloem-feeding insects.
A Soluble Guanylate Cyclase Mediates Negative Signaling by Ammonium on Expression of Nitrate Reductase in Chlamydomonas
Authors: de Montaigu Amaury , Sanz-Luque Emanuel , Galván Aurora , Fernández Emilio
Published: May 2010

Nitrate assimilation in plants and related organisms is a highly regulated and conserved pathway in which the enzyme nitrate reductase (NR) occupies a central position. Although some progress has been made in understanding the regulation of the protein, transcriptional regulation of the NR gene (NIA1) is poorly understood. This work describes a mechanism for the ammonium-mediated repression of NIA1. We report the characterization of a mutant defective in the repression of NIA1 and NR in response to ammonium and show that a gene (CYG56) coding for a nitric oxide (NO)-dependent guanylate cyclase (GC) was interrupted in this mutant. NO donors, cGMP analogs, a phosphodiesterase inhibitor isobutylmethylxanthine (IBMX), and a calcium ionophore (A23187) repress the expression of NIA1 in Chlamydomonas reinhardtii wild-type cells and also repress the expression of other ammonium-sensitive genes. In addition, the GC inhibitors LY83,583 (6-anilino-5,8-quinolinedione) and ODQ (1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one) release cells from ammonium repression. Intracellular NO and cGMP levels were increased in the presence of ammonium in wild-type cells. In the cyg56 mutant, NIA1 transcription was less sensitive to NO donors and A23187, but responded like the wild type to IBMX. Results presented here suggest that CYG56 participates in ammonium-mediated NIA1 repression through a pathway that involves NO, cGMP, and calcium and that similar mechanisms might be occurring in plants.
Alteration of Substrate Specificity: The Variable N-Terminal Domain of Tobacco Ca2+-Dependent Protein Kinase Is Important for Substrate Recognition
Authors: Ito Takeshi , Nakata Masaru , Fukazawa Jutarou , Ishida Sarahmi , Takahashi Yohsuke
Published: May 2010

Protein kinases are major signaling molecules that are involved in a variety of cellular processes. However, the molecular mechanisms whereby protein kinases discriminate specific substrates are still largely unknown. Ca2+-dependent protein kinases (CDPKs) play central roles in Ca2+ signaling in plants. Previously, we found that a tobacco (Nicotiana tabacum) CDPK1 negatively regulated the transcription factor REPRESSION OF SHOOT GROWTH (RSG), which is involved in gibberellin feedback regulation. Here, we found that the variable N-terminal domain of CDPK1 is necessary for the recognition of RSG. A mutation (R10A) in the variable N-terminal domain of CDPK1 reduced both RSG binding and RSG phosphorylation while leaving kinase activity intact. Furthermore, the R10A mutation suppressed the in vivo function of CDPK1. The substitution of the variable N-terminal domain of an Arabidopsis thaliana CDPK, At CPK9, with that of Nt CDPK1 conferred RSG kinase activities. This chimeric CDPK behaved according to the identity of the variable N-terminal domain in transgenic plants. Our results open the possibility of engineering the substrate specificity of CDPK by manipulation of the variable N-terminal domain, enabling a rational rewiring of cellular signaling pathways.
On the accurate bond-valence parameters for the Sb3+/O2−ion pair
Authors: Sidey Vasyl
Published: May 2010

The improved values of the bond-valence parameters for the Sb3+/O2–ion pair,r0= 1.927 Å andb= 0.446 Å, have been deduced from the crystal structures of the α and β polymorphs of Sb2O3and from the set of precisely determined complex structures containing [Sb3+On] coordination shells.
Polymorphism in the nitrate salt of the [Mn(acetylacetonate)2(H2O)2]+ ion
Authors: Biju A. R. , Rajasekharan M. V.
Published: May 2010

The crystallization of [Mn(acac)2(H2O)2]+ from solutions containing excess nitrate leads to the formation of four polymorphs. All polymorphs contain two different types of complex ions, one containing essentially coplanar acac ligands and the other in which the two acac ligands together assume a chair conformation. Molecular modelling using DFT (density-functional theory) calculations shows that the coplanar conformation is the electronically stable one. The hydrogen bonding between the trans-water molecules and the nitrate ion produces a one-dimensional chain of 12-membered rings, which are further organized into a two-dimensional network via a lattice water molecule. Lattice-energy calculations have been carried out to compare the stabilities of the four polymorphs.
Towards a generalized vision of oxides: disclosing the role of cations and anions in determining unit-cell dimensions
Authors: Vegas Ángel , Mattesini Maurizio
Published: May 2010

Theoretical calculations of the electron-localization function show that, at the volumes of the two CaO phases (rocksalt and CsCl type), the parent Ca structures (fcc: face-centred cubic andsc: simple cubic, respectively) exhibit charge concentration zones which coincide with the positions occupied by the O atoms in their oxides. Similar features, also observed for the pairs Ca/CaF2and BaSn/BaSnO3, are supported by recent high-pressure experiments as well as electron-localization function (ELF) calculations, carried out on elemental K. At very high pressures, the elemental K adopts thehP4 structure, topologically identical to that of the K atoms in high-pressure K2S and high-temperature α-K2SO4. Moreover, the ELF for thehP4 structure shows charge concentration (∼ 2 electrons) at the sites occupied by the S atoms in the high-pressure K2S phase. All these features confirm the oxidation/high-pressure equivalence as well as the prediction of how cation arrays should be metastable phases of the parent metals. For the first time to our knowledge, the structure type, dimension and topology of several oxides and fluorides (CaO, CaF2and BaSnO3) are explained in univocal physical terms.
The evolution of tropical adaptation: comparing taurine and zebu cattle
Authors: Chan E. K. F. , Nagaraj S. H. , Reverter A.
Published: May 2010

Beef cattle breeds consist of three major genetic subdivisions. The taurine group is adapted to temperate environments, and the zebu and Sanga groups are both adapted to tropical environments. With the advent of genotyping and sequencing technologies in agriculture, genome‐wide exploration of the genetic basis for the differences in tropical adaptation has only just become possible. In this study, approximately 9000 single nucleotide polymorphism markers were genotyped on 317 animals of a selection of taurine, zebu, and composite breeds to characterize any systematic differences between these groups. We identified 91 intra‐breed‐class markers; 78 were polymorphic only within the zebu animals, while 13 were polymorphic only in the taurine animals. There were no fixed differences (fixed for alternate alleles between the two breed types) between zebu and taurine animals. We found 14 regions with significantly different allele frequencies between zebu and taurine animals indicative of variable selection pressure or genetic drift. We also found 12 independent regions of differential extended haplotype homozygosity (EHH), indicative of recent selection or rapid fixation of the alternate allele within a short period of time in one of the two breed classes. A preliminary functional genomics analysis of these regions pointed towards signatures of tropical attributes including keratins, heat‐shock proteins and heat resistance genes. We anticipate this investigation to be a stepping‐stone for future studies to identify genomic regions specific to the two cattle groups, and to subsequently assist in the discrimination between temperate and tropically adapted cattle.
Genetic association between bovine NOD2 polymorphisms and infection by Mycobacterium avium subsp. paratuberculosis in Holstein‐Friesian cattle
Authors: Ruiz‐Larrañaga O. , Garrido J. M. , Iriondo M. , Manzano C. , Molina E. , Koets A. P. , Rutten V. P. M. G. , Juste R. A. , Estonba A.
Published: May 2010

Nucleotide‐Binding Oligomerization Domain 2 (NOD2) has been reported to be a candidate gene for Mycobacterium avium subsp. paratuberculosis (MAP) infection in a Bos taurus × Bos indicus mixed breed based on a genetic association with the c.2197T>C single nucleotide polymorphism (SNP). Nevertheless, this SNP has also been reported to be monomorphic in the B. taurus species. In the present work, 18 SNPs spanning the bovine NOD2 gene have been analysed in a genetic association study of two independent populations of Holstein‐Friesian cattle. We found that the C allele of SNP c.*1908C>T, located in the 3′‐UTR region of the gene, is significantly more frequent in infected animals than in healthy ones, which supports the idea that the bovine NOD2 gene plays a role in susceptibility to MAP infection. However, in silico analyses of the NOD2 nucleotide sequence did not yield definitive data about a possible direct effect of SNP c.*1908C>T on susceptibility to infection and led us to consider its linkage disequilibrium with the causative variant. A more exhaustive genetic association study including all putative, functional SNPs from this gene and subsequent functional analyses needs to be conducted to achieve a more complete understanding of how different variants of NOD2 may affect susceptibility to MAP infection in cattle.
Altered natural killer (NK) cell frequency and phenotype in latent autoimmune diabetes in adults (LADA) prior to insulin deficiency
Authors: Åkesson C , Uvebrant K , Oderup C , Lynch K , Harris R A , Lernmark Å , Agardh C-D , Cilio C M
Published: May 2010

Approximately 10% of the patients diagnosed with type 2 diabetes (T2D) have detectable serum levels of glutamic acid decarboxylase 65 autoantibodies (GADA). These patients usually progress to insulin dependency within a few years, and are classified as being latent autoimmune diabetes in adults (LADA). A decrease in the frequency of peripheral blood natural killer (NK) cells has been reported recently in recent-onset T1D and in high-risk individuals prior to the clinical onset. As NK cells in LADA patients have been investigated scarcely, the aim of this study was to use multicolour flow cytometry to define possible deficiencies or abnormalities in the frequency or activation state of NK cells in LADA patients prior to insulin dependency. All patients were GADA-positive and metabolically compensated, but none were insulin-dependent at the time blood samples were taken. LADA patients exhibited a significant decrease in NK cell frequency in peripheral blood compared to healthy individuals (P = 0.0018), as reported previously for recent-onset T1D patients. Interestingly, NKG2D expression was increased significantly (P < 0.0001), whereas killer cell immunoglobulin-like receptor (KIR)3DL1 expression was decreased (P < 0.0001) within the NK cell population. These observations highlight a defect in both frequency and activation status of NK cells in LADA patients and suggest that this immunological alteration may contribute to the development of autoimmune diabetes by affecting peripheral tolerance. Indeed, recent evidence has demonstrated a regulatory function for NK cells in autoimmunity. Moreover, the decrease in NK cell number concords with observations obtained in recent-onset T1D, implying that similar immunological dysfunctions may contribute to the progression of both LADA and T1D.
Could a loss of memory T cells limit responses to hepatitis C virus (HCV) antigens in blood leucocytes from patients chronically infected with HCV before and during pegylated interferon-α and ribavirin therapy?
Authors: Lee S , Hammond T , Watson M W , Flexman J P , Cheng W , Fernandez S , Price P
Published: May 2010

The proportions and activation status of T cells may influence responses to hepatitis C virus (HCV) and treatment outcome in patients receiving pegylated interferon (IFN)-α/ribavirin therapy. We confirmed that IFN-γ enzyme-linked immunospot (ELISPOT) responses to HCV are poor in HCV patients and showed that responses to HCV and cytomegalovirus (CMV) antigens decrease during therapy. This was most apparent in patients with sustained virological response (SVR). Baseline frequencies of CD4+ effector memory (TEM) T cells were lower in SVR than non-SVR. Proportions of CD4+ and CD8+ TEM and terminally differentiated effector memory (TEMRA) T cells declined on therapy in SVR, as did proportions of Fas+ CD8+ TEMRA T cells. Baseline frequencies of programmed death (PD)-1-expressing CD4+ TEM and TEMRA T-cells were higher in SVR. Therapy increased percentages of PD-1+ CD4+ central memory (TCM) T cells and PD-1+ CD8+ TEM and TEMRA T cells in SVR. We conclude that successful therapy depletes circulating antigen-specific CD4+ T cell responses. This paralleled decreases in proportions of effector memory T cells and higher percentages of CD4+ TCM T cells expressing PD-1.
Polymerase chain reaction (PCR) detection of B cell clonality in Sjögren's syndrome patients: a diagnostic tool of clonal expansion
Authors: Guzmán L M , Castillo D , Aguilera S O
Published: May 2010

Sjögren's syndrome (SS) is an autoimmune disease characterized by clonal B cell attack of the exocrine glands and dysregulated expression of B cell-activating factor (BAFF). Based upon the current data of increased rates of lymphoid malignancy, as non-Hodgkin's lymphoma (NHL) is associated with SS, we propose the detection of clonal rearrangements of immunoglobulin heavy chain (IgH) gene in those patients as a predictor of malignant clonal expansion. To test our proposal, we examined the IgH clonal rearrangements in SS patients (60) and healthy control subjects (42) having chronic non-specific sialadenitis, to determine the presence of clonal B cells in minor labial salivary glands (MSG) of SS patients. Clonal B cell expansion was assessed by two polymerase chain reaction (PCR) assays: (i) semi-nested PCR, against sequences encoding framework regions FR3, FR2 and FR1c of the variable chain IgH gene in B cells present in the MSG infiltrate; and (ii) the PCR–enzyme-linked immunosorbent assay (ELISA) technique, against the major and minor breakpoint regions of the Bcl-2 oncogene coupled with a variable segment of the IgH to assess the Bcl-2/JH translocation. When FR3, FR2 and FR1c primers were employed, we detected B cell monoclonality in 87% of the SS patients and 19% of the control subjects. The association between inflammation severity of the MSG pattern and the presence of B cell clonality was found to be statistically significant (P < 0·01). We concluded that the presence of B cell clonality in MSG can be used as a index of an altered microenvironment favouring the development of lymphoma in SS patients.
Changes in the levels of some acute-phase proteins in human immunodeficiency virus-1 infected patients, following interleukin-2 treatment
Authors: Barbai V H , Ujhelyi E , Szlávik J , Vietorisz I , Varga L , Fey E , Füst G , Bánhegyi D
Published: May 2010

Intermittent interleukin (IL)-2 administration to human immunodeficiency virus (HIV)-1 infected patients is well documented and generally used, but there is limited information about the changes of acute-phase protein (APP) levels in response to this treatment. Fifteen patients undergoing highly active anti-retroviral therapy (HAART) treatment, with undetectable viral load, but low CD4+ cell count (<300/µl), have been treated with 3·6 M IU Proleukine® administered twice daily by subcutaneous injection over 5 days. C-reactive protein (CRP), d-dimer, C3, C9, C1-inh and alpha-2HS glycoprotein levels were measured immediately before IL-2 administration, as well as on day 5 and 2–3 weeks thereafter. After IL-2 administration, both mean d-dimer and CRP levels increased significantly (P < 0·001), but returned (P < 0·001) to baseline within the subsequent 2–3 weeks. Alpha-2HS glycoprotein decreased immediately after IL-2 administration. No significant differences were detected in the levels of C3, C9 and C1-inh. A significant, positive correlation (r = 0·5178, P = 0·0008) was ascertained between the changes of CRP level, measured immediately before as well as 5 days after IL-2 administration, and changes in CD4 T cell counts measured 2–3 weeks before and after treatment, respectively. IL-2 administration induces rapid elevation of two major APPs (CRP, d-dimer). The positive correlation observed between the changes of CRP levels and CD4+ cell counts after IL-2 administration may indicate that the abrupt, but transitory overproduction of CRP might contribute to the CD4+ cell count-increasing effect of the drug and/ or may be associated with serious side effects.
Survival in rectal cancer is predicted by T cell infiltration of tumour-associated lymphoid nodules
Authors: McMullen T P W , Lai R , Dabbagh L , Wallace T M , De Gara C J
Published: May 2010

Lymphoid nodules are a normal component of the mucosa of the rectum, but little is known about their function and whether they contribute to the host immune response in malignancy. In rectal cancer specimens from patients with local (n = 18), regional (n = 12) and distant (n = 10) disease, we quantified T cell (CD3, CD25) and dendritic cell (CD1a, CD83) levels at the tumour margin as well as within tumour-associated lymphoid nodules. In normal tissue CD3+, but not CD25+, T cells are concentrated at high levels within lymphoid nodules, with significantly fewer cells found in surrounding normal mucosa (P = 0·001). Mature (CD83), but not immature (CD1a), dendritic cells in normal tissue are also found clustered almost exclusively within lymphoid nodules (P = < 0·0001). In rectal tumours, both CD3+ T cells (P = 0·004) and CD83+ dendritic cells (P = 0·0001) are also localized preferentially within tumour-associated lymphoid nodules. However, when comparing tumour specimens to normal rectal tissue, the average density of CD3+ T cells (P = 0·0005) and CD83+ dendritic cells (P = 0·0006) in tumour-associated lymphoid nodules was significantly less than that seen in lymphoid nodules in normal mucosa. Interestingly, regardless of where quantified, T cell and dendritic cell levels did not depend upon the stage of disease. Increased CD3+ T cell infiltration of tumour-associated lymphoid nodules predicted improved survival, independent of stage (P = 0·05). Other T cell (CD25) markers and different levels of CD1a+ or CD83+ dendritic cells did not predict survival. Tumour-associated lymphoid nodules, enriched in dendritic cells and T cells, may be an important site for antigen presentation and increased T cell infiltration may be a marker for improved survival.
T cell responses induced by allergen-specific immunotherapy
Authors: Maggi E
Published: May 2010

Allergen-specific immunotherapy is recognized as a highly effective practice in the treatment of patients with severe allergic rhinitis and/or asthma and is recommended by World Health Organization as an integrated part of allergy management strategy. Several studies have shown that allergen-specific immunotherapy, based on the administration of increasing doses of allergen, achieves a hyposensitization and reduces both early and late responses occurring during the natural exposure to the allergen itself. This is the unique antigen-specific immunomodulatory treatment in current use for human diseases. Successful immunotherapy is associated with reductions in symptoms and medication scores and improved quality of life. After interruption it usually confers long-term remission of symptoms and prevents the onset of new sensitizations in children up to a number of years. Subcutaneous immunotherapy usually suppresses the allergen-induced late response in target organs, likely due to the reduction of the infiltration of T cells, eosinophils, basophils, mast cells and neutrophils. In addition to the reduction of cells of allergic inflammation, immunotherapy also decreases inflammatory mediators at the site of allergen exposure. This review provides an update on the immunological T cell responses induced by conventional subcutaneous and sublingual immunotherapy, and gives a unifying view to reconciling the old dualism between immunoredirecting and immunoregulating mechanisms.