bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased plasma angiotensin II in postural tachycardia syndrome (POTS) is related to reduced blood flow and blood volume
Authors: Stewart Julian M. , Glover June L. , Medow Marvin S. 
Published: January 2006

POTS (postural tachycardia syndrome) is associated with low blood volume and reduced renin and aldosterone; however, the role of Ang (angiotensin) II has not been investigated. Previous studies have suggested that a subset of POTS patients with increased vasoconstriction related to decreased bioavailable NO (nitric oxide) have decreased blood volume. Ang II reduces bioavailable NO and is integral to the renin–Ang system. Thus, in the present study, we investigated the relationship between blood volume, Ang II, renin, aldosterone and peripheral blood flow in POTS patients. POTS was diagnosed by 70° upright tilt, and supine calf blood flow, measured by venous occlusion plethysmography, was used to subgroup POTS patients. A total of 23 POTS patients were partitioned; ten with low blood flow, eight with normal flow and five with high flow. There were ten healthy volunteers. Blood volume was measured by dye dilution. All biochemical measurements were performed whilst supine. Blood volume was decreased in low-flow POTS (2.14±0.12 litres/m2) compared with controls (2.76±0.20 litres/m2), but not in the other subgroups. PRA (plasma renin activity) was decreased in low-flow POTS compared with controls (0.49±0.12 compared with 0.90±0.18 ng of Ang I·ml−1·h−1 respectively), whereas plasma Ang II was increased (89±20 compared with 32±4 ng/l), but not in the other subgroups. PRA correlated with aldosterone (r=+0.71) in all subjects. PRA correlated negatively with blood volume (r=−0.72) in normal- and high-flow POTS, but positively (r=+0.65) in low-flow POTS. PRA correlated positively with Ang II (r=+0.76) in normal- and high-flow POTS, but negatively (r=−0.83) in low-flow POTS. Blood volume was negatively correlated with Ang II (r=−0.66) in normal- and high-flow POTS and in five low-flow POTS patients. The remaining five low-flow POTS patients had reduced blood volume and increased Ang II which was not correlated with blood volume. The data suggest that plasma Ang II is increased in low-flow POTS patients with hypovolaemia, which may contribute to local blood flow dysregulation and reduced NO bioavailability.
Short‐term longitudinal study of a child with Williams syndrome
Authors: Stojanovik Vesna , James Deborah 
Published: January 2006

AbstractBackground: The superiority of language and communication skills in children and adults with Williams syndrome (WS) is currently being debated. Whilst there have been a number of reports of precursors of language in WS in children who have already developed language, there have not been many studies that have prospectively investigated precursors of language in pre‐verbal children with WS.Aims: To investigate the development of early social communication skills before the onset of language in WS.Methods & Procedures: A short‐term longitudinal single case study was carried out spanning 10 months. The child was assessed five times using parent report, observation of mother—child interactions and by administering the Pre‐verbal Communication Schedule, the Pragmatics Profile of Early Communication Skills and the Pre‐School Language Scale − 3.Outcomes & Results: Longitudinal comparisons showed that the level of verbal communication in the child with WS always lagged behind the level of motor and cognitive development.Conclusions: The results indicate that rather than being a strength, social communication was an area of weakness relative to other aspects of development in this case. This case raises the potential desirability for early speech and language assessment and intervention in infants with WS.
Synergistic effects of plant‐growth promoting rhizobacteria andRhizobiumon nodulation and nitrogen fixation by pigeonpea (Cajanus cajan)
Authors: Tilak K. V. B. R. , Ranganayaki N. , Manoharachari C. 
Published: January 2006

SummaryPlant‐growth promoting rhizobacteria (PGPR), in conjuction with efficientRhizobium, can affect the growth and nitrogen fixation in pigeonpea by inducing the occupancy of introducedRhizobiumin the nodules of the legume. This study assessed the effect of different plant‐growth promoting rhizobacteria (Azotobacter chroococcum,Azospirillum brasilense,Pseudomonas fluorescens,Pseudomonas putidaandBacillus cereus) on pigeonpea (Cajanus cajan(L) Milsp.) cv. P‐921 inoculated withRhizobiumsp. (AR‐2–2 k). A glasshouse experiment was carried out with a sandy‐loam soil in which the seeds were treated withRhizobiumalone or in combination with several PGPR isolates. It was monitored on the basis of nodulation, N2fixation, shoot biomass, total N content in shoot and legume grain yield. The competitive ability of the introducedRhizobiumstrain was assessed by calculating nodule occupancy. The PGPR isolates used did not antagonize the introducedRhizobiumstrain and the dual inoculation with eitherPseudomonas putida,P. fluorescensorBacillus cereusresulted in a significant increase in plant growth, nodulation and enzyme activity overRhizobium‐inoculated and uninoculated control plants. The nodule occupancy of the introducedRhizobiumstrain increased from 50% (withRhizobiumalone) to 85% in the presence ofPseudomonas putida. This study enabled us to select an ideal combination of efficientRhizobiumstrain and PGPR for pigeonpea grown in the semiarid tropics.
Root, rhizosphere and root‐free respiration in soils under grassland and forest plants
Authors: Chen C. R. , Condron L. M. , Xu Z. H. , Davis M. R. , Sherlock R. R 
Published: January 2006

SummaryPlants significantly affect rates of carbon (C) turnover in soils, both because they are sources of carbon through exudation in the rhizosphere and litter‐fall, and because rhizosphere microbes stimulated by roots also metabolize native soil carbon. Different plant species affect these components of soil carbon turnover in different ways, but the quantitative information on this is lacking for different ecosystems and soil‐plant combinations. To compare the effects of grassland and forest plant species on the components of rhizosphere respiration in different soils, we grew ryegrass (Lolium perenne) and radiata pine (Pinus radiata D. Don) in two silt loam soils in pots in a glasshouse, and in seven samplings over 45 weeks measured total (Rtotal), root (Rroot) and root‐free soil respiration (Rrfs), the latter from respiration in unplanted controls. We calculated rhizosphere respiration (Rrhizo), defined here as the net of that fuelled by native soil C and root‐derived C, from Rtotal less Rroot+Rrfs. We also measured plant growth and total, water‐soluble and microbial biomass C in the soils at each sampling. Results showed that Rrfs decreased over the experimental period in both soils. Under ryegrass, Rroot, Rrhizo and Rtotal increased up to 14 weeks after planting and then stabilized, whereas under radiata pine, they continued to increase throughout the experiment. By the end of the experiment, the Rroot, Rrhizo and Rrfs components accounted for 49–58, 31–50 and 1–11% of soil total respiration under ryegrass, respectively, and 43–66, 29–53 and 1–5% under radiata pine. The greater Rroot, Rrhizo and Rtotal values under radiata pine were related to greater root biomass and root‐derived organic C, and enhanced microbial mineralization of native soil organic C.
Modelling the rhizosphere: a review of methods for ‘upscaling’ to the whole‐plant scale
Authors: Darrah P. R. , Jones D. L. , Kirk G. J. D. , Roose T. 
Published: January 2006

SummaryThe rhizosphere is a dynamic region where multiple interacting processes in the roots and surrounding soil take place, with dimensions set by the distance to which the zone of root influence spreads into the soil. Its complexity is such that some form of mathematical modelling is essential for understanding which of the various processes operating are important, and a minimal model of the rhizosphere must provide information on (a) the spatiotemporal concentration changes of mobile solutes in the root‐influenced soil, and (b) the cumulative uptake of solutes per unit length of root over time. Both are unique for a given set of parameters and initial conditions and hence the model is fully deterministic. ‘Up‐scaling’ to uptake by whole plants by integrating individual fluxes requires a measure of the growth and senescence of the root system. Root architecture models are increasingly successful in providing this. The spatio‐temporal scales of the rhizosphere and roots are sufficiently different that they can be treated separately, and this greatly simplifies modelling. The minimal model has been successfully applied to the more‐mobile nutrients in soil, such as nitrate or potassium, but much less successfully to less‐soluble nutrients such as phosphorus, because other, undescribed processes become important. These include transfers from unavailable forms, heterogeneity of resource distribution, root competition, water redistribution and adaptive processes. Incorporating such processes into models can disrupt independent scaling. In general, scaling from the scale of the individual root to that of the whole plant does not pose insuperable problems. Paradoxically, the major challenge in introducing more complexity is that experimental corroboration of the model is required at the individual root scale.
Global tectonics under g having a minute westward tilt
Authors: Bostrom Robert C. 
Published: January 2006

AbstractThe convection seen to affect Moon's mantle takes place under gravity having a component of asymmetry, in the form of a minute westward slope or tilt constituting the external part of the field. Its effect is explored employing the equivalent potential, denominated . Its nature is to bias convection of internal origin, inducing east–west polarization of a type prominent in global tectonics. Separately, research at Harvard has shown that by causing advection of non‐hydrostatic masses within the heterogeneous mantle, deep‐seated convection inevitably displaces the axis of maximum moment, compelling polar wander. A reconstruction based on observed dissipation suggests that the combined effect of these factors is to contribute a not inconsiderable low‐latitude, surface‐west component to the structure of the convection. Cumulative alteration in the direction ‘west’ must eventually require global rearrangement of its cell structure, offering explanation of the abrupt Mesozoic–Tertiary transition and progressive net lithosphere rotation.
Methods and concepts in quantifying resistance to drought, salt and freezing, abiotic stresses that affect plant water status
Authors: Verslues Paul E. , Agarwal Manu , Katiyar‐Agarwal Surekha , Zhu Jianhua , Zhu Jian‐Kang 
Published: January 2006

SummaryThe abiotic stresses of drought, salinity and freezing are linked by the fact that they all decrease the availability of water to plant cells. This decreased availability of water is quantified as a decrease in water potential. Plants resist low water potential and related stresses by modifying water uptake and loss to avoid low water potential, accumulating solutes and modifying the properties of cell walls to avoid the dehydration induced by low water potential and using protective proteins and mechanisms to tolerate reduced water content by preventing or repairing cell damage. Salt stress also alters plant ion homeostasis, and under many conditions this may be the predominant factor affecting plant performance. Our emphasis is on experiments that quantify resistance to realistic and reproducible low water potential (drought), salt and freezing stresses while being suitable for genetic studies where a large number of lines must be analyzed. Detailed protocols for the use of polyethylene glycol‐infused agar plates to impose low water potential stress, assay of salt tolerance based on root elongation, quantification of freezing tolerance and the use of electrolyte leakage experiments to quantify cellular damage induced by freezing and low water potential are also presented.
Practical approaches to plant volatile analysis
Authors: Tholl Dorothea , Boland Wilhelm , Hansel Armin , Loreto Francesco , Röse Ursula S.R. , Schnitzler Jörg‐Peter 
Published: January 2006

SummaryPlants emit volatile organic compounds (VOCs) that play important roles in their interaction with the environment and have a major impact on atmospheric chemistry. The development of static and dynamic techniques for headspace collection of volatiles in combination with gas chromatography–mass spectrometry analysis has significantly improved our understanding of the biosynthesis and ecology of plant VOCs. Advances in automated analysis of VOCs have allowed the monitoring of fast changes in VOC emissions and facilitated in vivo studies of VOC biosynthesis. This review presents an overview of methods for the analysis of plant VOCs, including their advantages and disadvantages, with a focus on the latest technical developments. It provides guidance on how to select appropriate instrumentation and protocols for biochemical, physiological and ecologically relevant applications. These include headspace analyses of plant VOCs emitted by the whole organism, organs or enzymes as well as advanced on‐line analysis methods for simultaneous measurements of VOC emissions with other physiological parameters.
Measuring multiple fluxes through plant metabolic networks
Authors: Ratcliffe R.G. , Shachar‐Hill Y. 
Published: January 2006

SummaryFluxes through metabolic networks are crucial for cell function, and a knowledge of these fluxes is essential for understanding and manipulating metabolic phenotypes. Labeling provides the key to flux measurement, and in network flux analysis the measurement of multiple fluxes allows a flux map to be superimposed on the metabolic network. The principles and practice of two complementary methods, dynamic and steady‐state labeling, are described, emphasizing best practice and illustrating their contribution to network flux analysis with examples taken from the plant and microbial literature. The principal analytical methods for the detection of stable isotopes are also described, as well as the procedures for obtaining flux maps from labeling data. A series of boxes summarizing the key concepts of network flux analysis is provided for convenience.
Using intrinsically fluorescent proteins for plant cell imaging
Authors: Dixit Ram , Cyr Richard , Gilroy Simon 
Published: January 2006

SummaryThe intrinsically fluorescent proteins (IFPs), such as the green, cyan and yellow fluorescent proteins, have revolutionized how we can image the dynamics of cellular events. Intrinsically fluorescent proteins have been used as reporter genes to monitor transcriptional regulation, as targeted markers for organelles and subcellular structures, in fusion proteins to directly observe protein motility and dynamics, and in sensors designed to show changes in cellular environments ranging from pH to protein kinase activity. The IFPs hold tremendous potential to reveal the dynamic processes that underlie plant cell function; however, as with all technology there are artifacts and pitfalls inherent in their use. In this review, we highlight some of the practical issues in using IFPs for live cell imaging. These include choice of the appropriate IFP, dealing with autofluorescence, photobleaching and phototoxicity, and application of approaches such as fluorescence resonance energy transfer (FRET), fluorescence lifetime imaging (FLIM) and fluorescence recovery after photobleaching (FRAP) to gain high‐resolution data about protein dynamics within the cell. We also discuss some of the more common artifacts associated with these fluorescence imaging approaches and suggest controls that should help both spot these problems and suggest their solutions.
Microarray analysis of the transcriptome as a stepping stone towards understanding biological systems: practical considerations and perspectives
Authors: Clarke Joseph D. , Zhu Tong 
Published: January 2006

SummaryDNA microarrays have been used to characterize plant transcriptomes to answer various biological questions. While many studies have provided significant insights, there has been great debate about the general reliability of the technology and data analysis. When compared to well‐established transcript analysis technologies, such as RNA blot analysis or quantitative reverse transcription‐PCR, discrepancies have frequently been observed. The reasons for these discrepancies often relate to the technical and experimental systems. This review‐tutorial addresses common problems in microarray analysis and describes: (i) methods to maximize extraction of valuable biological information from the vast amount of microarray data and (ii) approaches to balance resource availability with high scientific standards and technological innovation with peer acceptability.
Polymorphism of HLA class II genes in Miao and Yao nationalities of Southwest China
Authors: Liu Y. , Liu Z. , Fu Y. , Jia Z. , Chen S. , Xu A. 
Published: January 2006

AbstractIn the present study, the polymorphism of human leucocyte antigen class II genes was investigated by the sequence‐based typing method in two Chinese populations: the Miaos (n = 85) from Guizhou province and the Yaos (n = 66) from Yunnan province. These two populations exhibited certain similarity in their allelic distributions. Among 24 DRB1 alleles detected, DRB1*150101, DRB1*140101, DRB1*160201 and DRB1*090102 in Miao and DRB1*120201, DRB1*140101, DRB1*150101 and DRB1*090102 in Yao were highly predominant. Sixteen DQB1 alleles in total were found in these two populations among which DQB1*050201, DQB1*060101/060103 and DQB1*030101/0309 in both Miao and Yao and DQB1*050301 in Yao were commonly observed. In the 13 DPB1 alleles detected, the most frequent allele was DPB1*0501 in Miao and Yao followed by DPB1*02 and DPB1*1301. Frequent comparisons with other Chinese populations suggested the southern Chinese feature for both the Miao and Yao nationalities.
NFκB1 gene does not affect type 1 diabetes predisposition in a Spanish population
Authors: Martínez A. , Santiago J. L. , De La Calle H. , Figueredo M. A. , Fernández‐Arquero M. , De La Concha E. G. , Urcelay E. 
Published: January 2006

AbstractThe chromosomal location of the NFκB1 gene on 4q, a region linked to type 1 diabetes (T1D), together with the observed resistance to T1D of NFκB1‐deficient mice, suggests its potential role as candidate gene increasing diabetes predisposition. Previous association studies in diverse populations yielded inconclusive results. Two polymorphisms in the promoter region of the NFκB1 gene have been studied: a functional −94ins/delATTG regulating the gene expression and a very informative CA‐repeat microsatellite. A strong association with the latter was reported in British population but could not be replicated in Danish families. No evidence of association was detected for those genetic markers in 270 Spanish T1D patients and 484 healthy ethnically matched controls. Therefore, it seems that this gene plays no major role in T1D predisposition.
HLA class II disease associations in southern Africa
Authors: Lombard Z. , Brune A. E. , Hoal E. G. , Babb C. , Van Helden P. D. , Epplen J. T. , Bornman L. 
Published: January 2006

AbstractSouthern Africa harbors several population groups representing a diversity of gene pool origins. This provides a unique opportunity to study genetic disease predisposition in these populations against a common environmental background. Human leukocyte antigen (HLA) association studies of these populations could improve knowledge on inter‐population variation and HLA‐related disease susceptibility. The aim of this paper is to review HLA class II disease associations reported for southern African population groups, compare them with findings in other populations and identify those unique to southern Africa. A number of HLA class II disease associations appear to be unique to southern African populations. These include DRB1*14011 association with insulin‐dependent diabetes mellitus susceptibility in the Xhosa and DRB1*10 and DQB1*0302 with rheumatoid arthritis susceptibility in the South African (SA) Indian and SA Coloreds, respectively. A noteworthy similarity in class II disease association was observed among southern African Caucasoid and their European parental populations. Unique HLA class II disease associations observed in southern Africa are consistent with the notion that unique environmental and natural selective factors have resulted in certain ethnic‐specific HLA class II disease associations, while common HLA class II disease associations found across different populations support the notion that common diseases are caused by common, ancient alleles present in indigenous African populations.
Identification and Pathogenicity of Rhizoctonia spp. Causing Wirestem of Betula nigra in China
Authors: Yang G.‐H. , Naito S. , Dong W. H. 
Published: January 2006

AbstractDuring July 2004, wirestem was frequently observed on the seedlings of Betula nigra at Dehong district in Yunnan Province, China. Isolates of Rhizoctonia spp. consistently obtained from their diseased leaves, roots and stems were identified as belonging to binucleate Rhizoctonia anastomosis groups (AG) AG‐P and AG‐R, and R. solani AG‐I IB and AG‐4 HG‐I, based on cultural characteristics, nuclear staining, anastomisis reaction and analysis of their ITS rDNA region. The percentage of recovery of AG‐P, AG‐1, AG‐R and AG‐4 was 48%, 39%, 8% and 3%, respectively. This is the first report of wirestem of red birch cause by binucleate Rhizoctonia AG‐P and AG‐R, and R. solani AG‐1 IB and AG‐4 HG‐I in China.
Relationships between Tospovirus Incidence and Thrips Populations on Tomato in Mendoza, Argentina
Authors: de Borbón C. M. , Gracia O. , Píccolo R. 
Published: January 2006

AbstractThe objectives of this work were to estimate the capability of local populations of thrips as vectors of groundnut ringspot virus (GRSV) and tomato spotted wilt virus (TSWV), and to determine the species composition of vectors in tomato crops. Transmission assays were performed. Incidence of tospoviruses was estimated in commercial crops. Random samples of flowers were taken from tomato for identification of thrips. Of the five species of thrips tested, Frankliniella gemina (first record), F. occidentalis and F. schultzei transmitted GRSV and TSWV. F. schultzei was a significantly more efficient vector of GRSV than F. occidentalis under controlled assay conditions. The thrips were identified on flowers from six surveyed tomato crops. F. occidentalis was the most frequently identified species (43.0%), followed by F. schultzei (35.6%) and Thrips tabaci (10.1%). The incidence of tospoviruses was low (1.1–2.8%) in crops planted during August–September and greater (9.5–61.1%) in crops planted in December. GRSV was prevalent (85%) over TSWV (11%).