bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of novel QTL for resistance to crown rot in the doubled haploid wheat population ‘W21MMT70’ × ‘Mendos’
Authors: Bovill W. D. , Ma W. , Ritter K. , Collard B. C. Y. , Davis M. , Wildermuth G. B. , Sutherland M. W.
Published: November 2006

Crown rot (causal agent Fusarium pseudograminearum) is a fungal disease of major significance to wheat cultivation in Australia. A doubled haploid wheat population was produced from a cross between line ‘W21MMT70’, which displays partial seedling and adult plant (field) resistance to crown rot, and ‘Mendos’, which is moderately susceptible in seedling tests but partially resistant in field trials. Bulked segregant analysis (BSA) based on seedling trial data did not reveal markers for crown rot resistance. A framework map was produced consisting of 128 microsatellite markers, four phenotypic markers, and one sequence tagged site marker. To this map 331 previously screened AFLP markers were then added. Three quantitative trait loci (QTL) were identified with composite interval mapping across all of the three seedling trials conducted. These QTL are located on chromosomes 2B, 2D and 5D. The 2D and 5D QTL are inherited from the line ‘W21MMT70’, whereas the 2B QTL is inherited from ‘Mendos’. These loci are different from those associated with crown rot resistance in other wheat populations that have been examined, and may represent an opportunity for pyramiding QTL to provide more durable resistance to crown rot.
Genetic diversity among parental lines of Indica hybrid rice (Oryza sativa L.) in China based on coefficient of parentage
Authors: Wang S. , Lu Z.
Published: November 2006

Genetic diversity constitutes the raw material for plant improvement, and provides protection against genetic vulnerability to biotic and abiotic stresses. Diversity of parental lines of indica hybrid rice in China is not well‐characterized. The major objective of this study was to quantify genetic diversity of Chinese parental lines of hybrid rice via coefficient of parentage (COP). All 100 parental lines of hybrid rice widely used in hybrid breeding and commercial production during 1976–2003 were studied by COP analysis. The mean COP for the 100 parental lines was low (0.056), indicating a potentially high degree of diversity in Chinese hybrid rice breeding. Forty‐nine percent of all pairs of parental lines were completely unrelated by pedigree data. The low mean COP for the parental lines was attributed to a continual incorporation of exotic germplasm (wild rice, japonica and javanica etc.) into the genetic base over time, to the introduction of foreign germplasm from the Philippines (International Rice Research Institute), Korea, the United States, Thailand, and Guyana as breeding stock. The mean COP from 1976 to 1990 was twice as much as that from 1990 to 2003. Cluster analysis was an effective method to discriminate diversity, ten clusters were identified, and maintainer lines, restorer lines and other parental lines with special genetic background were clearly grouped. In addition, restorer lines were further divided into 11 sub‐clusters, which basically was in agreement with hybrid rice breeding. Among ten provinces, Hunan, Sichuan and Fujian were outstanding for breeding 54 of 100 parental lines in hybrid rice production, and the genetic diversity of parental lines in Fujian, Sichuan,Guangxi, Hunan and Jiangsu were all narrower than that in Hubei, Guangdong, Zhejiang and Jiangxi. The result of coefficient of parentage analysis for 100 parental lines may promote the management of parental diversity and hybrid rice breeding in China.
Inheritance of cellular thermotolerance in bread wheat
Authors: Dhanda S. S. , Munjal R.
Published: November 2006

Leaf membrane stability (LMS) and the tetrazolium triphenyl chloride (TTC) test, heat susceptibility index (HSI), heat response index (HRI) and grain yield were used to evaluate 20 diverse wheat genotypes under normal and heat stress conditions for 2 years. The varieties ‘Seri’ and ‘Raj 3765’ had a desirable combination of cellular thermotolerance (TTC and LMS), heat tolerance (HRI) and high grain yield potential under heat stress, while ‘WH 730’ and ‘WH 533’ were better in cellular thermotolerance and heat tolerance. The varieties ‘PBW 373’ and ‘Kauz’ also performed better under heat stress in terms of grain yield and HSI/HRI. The varieties ‘Kanchan’, ‘PBW 373’, ‘NIAW 34’ and ‘GW 173’ were avoiders/escapers, ‘Seri’ and ‘HUW 234’ were tolerant to heat stress, while ‘WH 730’, ‘WH 533’, ‘Nesser’, ‘Raj 3765’ and ‘Kauz’ showed a combination of both. Correlation coefficients revealed that HRI was the most important trait, followed by TTC because the genotype having high HRI also had high grain yield and was better in mitochondrial viability and membrane stability under heat stress. Significance of GCA and SCA variances indicated the presence of both additive and dominant types of gene action. The use of the parents with high GCA effects, namely, ‘Raj 3765’ and ‘WH 730’ in a crossing programme for thermotolerance may provide desirable segregants through selection.
Characterization of a novel form of fertile great headed garlic (Allium sp.)
Authors: Hirschegger P. , Galmarini C. , Bohanec B.
Published: November 2006

A new form of great headed garlic (GHG), was collected, grown and utilized as garlic in the province of Mendoza, Argentina. It was found in contrast to other known forms of GHG that this novel form is fertile, while other characteristics remained unknown. Studies revealed that all accessions investigated formed large bulbs and produced fertile seeds, with a germination rate of around 30%. Genome size analysis and chromosome counting of the GHG accessions, made in comparison with hexaploid forms of GHG, revealed that the accessions were octoploid, with a genome size ranging from 119.5 to 122.4 pg. Preliminary karyotype analysis indicates a possible allopolyploid origin. It is suggested that this fertile accession deserves further attention as a novel source of genetic variation in ‘garlic‐like’ plants.
Organization and expression of the mitochondrial genome in CMS (Moricandia) Brassica juncea: nuclear‐mitochondrial incompatibility results in differential expression of the mitochondrial atpα gene
Authors: Gaikwad K. , Baldev A. , Kirti P. B. , Mohapatra T. , Bhat S. R. , Chopra V. , Prakash S.
Published: November 2006

The mitochondrial genome of CMS (Moricandia) Brassica juncea has been characterized. Southern analysis using nine different mt‐specific gene probes revealed differences between B. juncea and M. arvensis and the CMS line. A northern profile of flower bud and leaf mt RNA blots was found conserved for six genes tested. However, tissue‐specific expression was observed for atpα. A longer transcript was present in the bud tissue of the CMS line, which reverted to normal in the presence of the fertility restorer gene, while its expression was normal in the leaf tissues. The atpα gene was cloned from B. juncea, M. arvensis and the CMS line. Restriction mapping shows a high degree of restriction site conservation between the CMS and B. juncea lines with minor alterations at the 5′ and the 3′ ends, indicating the presence of an almost intact M. arvensisatpα gene in the CMS line harbouring a B. juncea nucleus. The results are discussed with respect to the potential role of atpα in generating male sterility in CMS (Mori) B. juncea.
Androgenetic plants of Anemone coronaria derived through anther culture
Authors: Laura M. , Safaverdi G. , Allavena A.
Published: November 2006

The genus Anemone (Ranunculaceae) includes many species cultivated for ornamental purposes. Most cut flower cultivars belong to A. coronaria L. and are multiplied by seed and sold for cultivation as 1‐year‐old tubers. As cultivars represent a population of hybrid individuals derived from crosses between heterozygous parents, the use of a true F1 hybrid would improve the uniformity and quality of the product. As a first step towards the development of pure‐breeding lines, anther cultures were established from elite cultivars of A. coronaria. Somatic embryos and plantlets were regenerated from five elite cultivars, and up to 16.9 regenerants per 100 cultured anthers were obtained. Cytological analysis identified that 11 of 19 regenerants had either a 2x = 16 karyotype, or were mixoploids. RAPD‐based DNA fingerprinting showed that all the regenerants tested differed genetically from their anther donor, confirming their androgenetic origin. The shortening to 15 months for the time required to produce homozygous lines may convince seed companies to invest in F1 hybrid breeding.
A major QTL effect controlling resistance to powdery mildew in winter wheat at the adult plant stage
Authors: Bougot Y. , Lemoine J. , Pavoine M.T. , Guyomar'ch H. , Gautier V. , Muranty H. , Barloy D.
Published: November 2006

Powdery mildew is one of the major diseases of wheat in regions with a maritime or semi‐continental climate which can strongly affect grain yield. The objective of the study was to identify and compare quantitative resistance to powdery mildew of line RE9001 at the adult plant and vernalized seedling stages. RE9001 has no known Pm gene and shows a high level of adult plant resistance in the field. Using 104 recombinant inbred lines (RILs) of an RE9001 × ‘Courtot’ F8 population, a genetic map was developed with 363 markers distributed over 26 linkage groups and covering 3825 cM. The global map density was 1 locus/10.3 cM. RILs were assessed under field and tunnel greenhouse conditions for 2 years in two locations. Eleven quantitative trait loci (QTL) were detected at the adult stage and they explained 63% of the variation, depending on the environment. Three QTLs were found, at least, in the two environments. One QTL from RE9001, mapped on chromosome 2B, was stable in each environment. This QTL, QPm.inra.2B, explained 10.3–36.6% of the variation and could be mapped in the vicinity of the Pm6 gene. At the vernalized seedling stage, one QTL detected by the isolate 93‐27 could be an allele of the Pm3g gene present in ‘Courtot’. No residual effect of the Pm3g gene was detected at either stage. Markers flanking the QTL 2B could be useful tools to combine resistance to powdery mildew in wheat cultivars.
An extension of the Smith model for quantitative genetic analysis of selection response under recurrent selection
Authors: Melchinger A. E. , Flachenecker C.
Published: November 2006

Selection and random genetic drift are the main forces affecting selection response in recurrent selection (RS) programmes. The correct assessment of both forces allows a better comparison of the efficiency of different RS schemes. The objective of this study was to extend the population diallel analysis proposed by Hammond and Gardner in 1974 and the model proposed by Smith in 1979 with full consideration of inbreeding depression due to random genetic drift. The effect of random genetic drift is expected to be large, particularly in studies with many selection cycles and/or high rates of inbreeding. Therefore, the extension of the population diallel allows a better assessment of the selection response in RS programmes.
Extending lifetime of plastic changes in the human brain
Authors: Nyffeler Thomas , Wurtz Pascal , Lüscher Hans‐Rudolf , Hess Christian W. , Senn Walter , Pflugshaupt Tobias , Von Wartburg Roman , Lüthi Mathias , Müri René M.
Published: November 2006

The ability of the brain to adjust to changing environments and to recover from damage rests on its remarkable capacity to adapt through plastic changes of underlying neural networks. We show here with an eye movement paradigm that a lifetime of plastic changes can be extended to several hours by repeated applications of theta burst transcranial magnetic stimulation to the frontal eye field of the human cortex. The results suggest that repeated application of the same stimulation protocol consolidates short‐lived plasticity into long‐lasting changes.
Hypothalamic proopiomelanocortin (POMC) neurons have a cholinergic phenotype
Authors: Meister Björn , Gömüç Burçak , Suarez Elisabet , Ishii Yuko , Dürr Katrin , Gillberg Linda
Published: November 2006

Neuronal networks originating in the hypothalamic arcuate nucleus play fundamental roles in the control of energy balance. Neuropeptide Y (NPY)‐producing neurons in the arcuate nucleus stimulate food intake, whereas arcuate nucleus neurons that release the proopiomelanocortin (POMC)‐derived peptide α‐melanocyte‐stimulating hormone (α‐MSH) potently reduce food intake. Relatively little attention has been focused on classical neurotransmitters in regulation of food intake. Here, we have investigated the potential presence of acetylcholine (ACh) in NPY‐ and POMC‐containing neuronal populations of the arcuate nucleus. Antisera to proteins required for cholinergic neurotransmission, including choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (VAChT), were employed in double‐labeling immunohistochemical experiments. In colchicine‐treated rats, ChAT‐ and VAChT‐immunopositive cell bodies were located in the ventral aspect of the arcuate nucleus. ChAT and VAChT immunoreactivities were demonstrated in α‐MSH‐ and cocaine‐ and amphetamine‐regulated transcript (CART)‐containing cell bodies of the arcuate nucleus, whereas cell bodies containing NPY or agouti‐related peptide (AGRP) were distinct from VAChT‐immunoreactive neuronal perikarya. VAChT immunoreactivity was also present in a large number of α‐MSH‐containing nerve fiber varicosities throughout the central nervous system. In the commissural part of the nucleus tractus solitarius, no α‐MSH‐containing cell bodies were found to have ChAT or VAChT immunoreactivity. The presence of markers for cholinergic neurotransmission in a subpopulation of hypothalamic POMC/CART neurons suggests co‐release of ACh with peptides derived from the POMC precursor and CART. The results indicate a role for ACh in control of energy balance, mediating the effects of peripheral hormones such as leptin and insulin.
Early deprivation leads to altered behavioural, autonomic and endocrine responses to environmental challenge in adult Fischer rats
Authors: Rüedi‐Bettschen Daniela , Zhang Weining , Russig Holger , Ferger Boris , Weston Anna , Pedersen Else‐Marie , Feldon Joram , Pryce Christopher R.
Published: November 2006

Depression is diagnosed on the basis of abnormal positive affects (anhedonia) and negative affects (low mood, helplessness, coping deficit, fatigue), and associated physiological abnormalities include hyperactivity of the HPA endocrine system and autonomic nervous system. Adverse early life environments, including parent–offspring emotional and physical neglect, are associated with traits of altered physiological and neurobiological function and long‐term predisposition to depression. Animal studies based on early life adversity can potentially yield environmental models of the developmental behavioural neurobiology of depression. In Wistar rats, we demonstrated that isolation of pups from dam and littermates at room temperature for 4 h per day on P1–14 (early deprivation, ED) led to adulthood anhedonia‐like traits of reduced motivation to obtain gustatory reward and reduced social motivation, relative to subjects left undisturbed during infancy (non‐handling, NH). We hypothesized that the depression‐like effects of ED would be even more pronounced and multiple in the stress hyper‐responsive Fischer rat strain. The effects of ED were studied relative to NH and 15 min of daily isolation (early handling, EH). Relative to NH and EH, which exhibited remarkably similar phenotypes, ED led, principally in males, to chronic traits of: reduced motivation for and consumption of gustatory reward; increased activity in the pre‐test and test phases of the forced swim test; reduced coping behaviour in an aversive environment; attenuated plasma corticosterone stress response to a normal plasma ACTH stress response; increased hypertensive response to a novel environment; and increased prefrontal cortical serotonin. High sensitivity to an aversive early environment in male Fischer rats therefore constitutes an important model for the study of affective development and its neurobiology.
Nicotine withdrawal suppresses nicotinic modulation of long‐term potentiation induction in the hippocampal CA1 region
Authors: Yamazaki Yoshihiko , Fujii Satoshi , Jia Yousheng , Sumikawa Katumi
Published: November 2006

We have previously reported that acute and chronic nicotine exposure lower the threshold for long‐term potentiation (LTP) induction in the rat hippocampal CA1 region, and acute application of nicotine in the chronic‐nicotine‐treated hippocampus further reduces the threshold. However, it is unknown how withdrawal from chronic nicotine exposure affects the induction of LTP. Here, we show that, following nicotine withdrawal, the threshold for LTP induction fluctuates before returning to the basal level and acute nicotine is no longer effective in lowering the threshold at 4 days after withdrawal. Chronic nicotine‐induced enhancement of N‐methyl‐d‐aspartate receptor responses slowly diminishes and returns to the control level by 8 days of withdrawal. In 4‐day‐withdrawn hippocampi, there is functional up‐regulation of postsynaptic α7 nicotinic acetylcholine receptors (nAChRs) on interneurons in the stratum radiatum, whereas the release of γ‐aminobutyric acid from their terminals is reduced. In both control and chronic nicotine‐exposed hippocampi, acute nicotine depresses monosynaptic inhibitory postsynaptic currents recorded in pyramidal cells but has almost no effect at 4 days of withdrawal. The lack of effect is due, at least in part, to the loss of a presynaptic nicotine effect. These withdrawal‐induced changes are accompanied by decreases in normal nicotine‐induced enhancement of N‐methyl‐d‐aspartate receptor responses, which may be responsible for the lack of acute nicotine‐mediated facilitation of LTP induction in 4‐day‐withdrawn hippocampi. These withdrawal‐induced changes may contribute to the cellular basis of unpleasant withdrawal symptoms and, thus, nicotine dependence.
Stress reverses plasticity in the pathway projecting from the ventromedial prefrontal cortex to the basolateral amygdala
Authors: Maroun Mouna
Published: November 2006

We have previously shown that high‐frequency stimulation to the basolateral amygdala (BLA) induces long‐term potentiation (LTP) in the ventromedial prefrontal cortex (vmPFC) and that prior exposure to inescapable stress inhibits the induction of LTP in this pathway [Maroun & Richter‐Levin (2003)J. Neurosci., 23, 4406–4409]. Here, we show that the reciprocal pathway projecting from the vmPFC to the BLA is resistant to the induction of LTP. Conversely, long‐term depression (LTD) is robustly induced in the BLA in response to low‐frequency stimulation to the vmPFC. Furthermore, prior exposure to inescapable stress reverses plasticity in this pathway, resulting in the promotion of LTP and the inhibition of LTD. Our findings suggest that, under normal and safe conditions, the vmPFC is unable to exert excitatory synaptic plasticity over the BLA; rather, LTD, which encodes memory of safety in the BLA, is favoured. Following stressful experiences, LTP in the BLA is promoted to encode memory of fear.
Coordination of presynaptic and postsynaptic maturation in a zebra finch forebrain motor control nucleus during song learning
Authors: Wang Jian , Hessler Neal A.
Published: November 2006

While some species of birds retain the ability to learn new songs as adults, many species can only learn during a restricted period when young. Previous studies have suggested that one potential mechanism of such a limited learning period, an alteration in the composition of postsynaptic NMDA receptors, does not competely block further song learning. Here, we examined whether presynaptic function could play a role in the regulation of learning capacity. We first showed that the participation of NMDA receptor NR2B subunits in synaptic currents in the robust nucleus of the arcopallium (RA), a critical location for integration of signals during song learning by young birds, decreases from young birds to adults. Using release‐dependent block of postsynaptic NMDA receptors by an open‐channel antagonist to assay presynaptic function, we showed that transmitter release at RA synapses from both HVC and the lateral magnocellular nucleus of the anterior nidopallium systematically decreases during the period of song learning, and in adults is about half that of juveniles. Further, activation of postsynaptic NMDA receptors could induce an acute depression of transmitter release, while lack of exposure to a normal learning environment could delay the developmental reduction in transmitter release. These results suggest that regulation of learning capacity may occur in part by coordination of presynaptic and postsynaptic function.
N‐ethylmaleimide increases release probability at GABAergic synapses in layer I of the mouse visual cortex
Authors: Kirmse Knut , Kirischuk Sergei
Published: November 2006

The sulphydryl alkylating agent N‐ethylmaleimide (NEM) has been often used as an uncoupler of pertussis toxin‐sensitive G‐proteins. However, the effects of NEM on γ‐aminobutyric acid (GABA)ergic synaptic transmission remain controversial. Using the whole‐cell patch‐clamp technique, GABAA receptor‐mediated postsynaptic currents (IPSCs) have been recorded from Cajal‐Retzius (CR) cells in layer I of the neonatal mouse visual cortex. NEM increased the frequencies of both spontaneous and miniature IPSCs (mIPSCs) without an effect on the median mIPSC amplitudes or mIPSC kinetics. The NEM actions on mIPSCs did not depend on the extracellular Ca2+, Ca2+ release from intracellular stores, adenylyl cyclase and protein kinase A activities. NEM increased the mean amplitudes of evoked IPSCs and strongly decreased the paired‐pulse ratio. The size of the readily releasable pool of presynaptic vesicles (RRP) was estimated using a high‐frequency stimulation protocol. The RRP size was not affected by NEM. In addition, NEM significantly decreased the latency between the stimulus and the onset of GABA release. These results suggest that NEM selectively increases GABA release probability. At postnatal day 2, mIPSCs were observed only in about 30% of CR cells. NEM application revealed, however, that more than 90% of CR cells receive GABAergic inputs. Therefore, NEM seems to be a useful tool to verify the existence of ‘silent’ GABAergic synapses.
Lipo‐prostaglandin E1 in combination with steroid therapy is effective for treatment of sudden sensorineural hearing loss in Korean patients with Type 2 diabetes
Authors: Ahn J. H. , Kim T. Y. , Kim Y.‐J. , Han M. W. , Yoon T. H. , Chung J. W.
Published: November 2006

Background  Diabetes mellitus is a risk factor for sudden sensorineural hearing loss (SSNHL), possibly as a result of microvascular damage, increased blood viscosity and embolic and thrombotic episodes.

Aim  To perform a prospective, randomized clinical trial to determine the therapeutic effect of lipo‐prostaglandin E1 (lipo‐PGE1) on SSNHL in Korean patients with Type 2 diabetes.

Methods  The study group consisted of 270 consecutive Korean patients (130 male, 140 female) in whom SSNHL was diagnosed. Patients were classified as diabetic or non‐diabetic by the new American Diabetes Association criteria. With the approval of the institute ethics committee, patients were randomly assigned to treatment with of 10 µg lipo‐PGE1 (lipo‐PGE1 group) given as a continuous infusion over 5 days, or saline (placebo group). In addition, all patients studied were treated with 48 mg methylprednisolone for 5 days.

Results  The overall recovery rates after treatment were 51.5% in diabetic and 64.2% in non‐diabetic patients. In diabetic patients, there was a significantly higher rate of hearing improvement in the lipo‐PGE1 group (64.7%) compared with the placebo group (37.5%), whereas, in non‐diabetic patients, there was no significant difference in rate of hearing improvement between the lipo‐PGE1 group (70.3%) and the placebo group (58.3%).

Conclusion  Lipo‐PGE1 may have beneficial effects in the treatment of SSNHL in Korean patients with Type 2 diabetes.
Oxidative burden in prediabetic and diabetic individuals: evidence from plasma coenzyme Q10
Authors: Lim S. C. , Tan H. H. , Goh S. K. , Subramaniam T. , Sum C. F. , Tan I. K. , Lee B. L. , Ong C. N.
Published: November 2006

Aim  Individuals with diabetes and prediabetes are at risk of vascular injury. However, the exact mechanisms are unclear. The mitochondria mobile electron carrier coenzyme Q10 (CoQ10) is a potent lipophilic antioxidant. We hypothesize that oxidative stress, detectable as changes in plasma CoQ10 concentrations and composition, plays an important role in vascular disease in diabetes.

Methods  We measured plasma CoQ10 concentrations (including reduced ubiquinol and oxidized ubiquinone subfractions) in 60 subjects with normal glucose tolerance [NGT; fasting plasma glucose (FPG) < 5.5 mmol/l], 63 with impaired fasting glucose (IFG; FPG 5.6–6.9 mmol/l) and 69 with Type 2 diabetes (DM; FPG > 6.9 mmol/l).

Results  In men and women, the total CoQ10/total cholesterol ratio was reduced in DM (mean ±sd) [male (M) 0.09 ± 0.04; female (F) 0.07 ± 0.04] compared with NGT (0.29 ± 0.08; 0.21 ± 0.07) and IFG (0.27 ± 0.07; 0.23 ± 0.07) (DM vs. NGT and IFG P = 0.001). A stepwise reduction in the plasma ubiquinol fraction (ubiquinol/total CoQ10) was observed from NGT (M 0.93 ± 0.06; F 0.95 ± 0.06) compared with IFG (0.43 ± 0.25; 0.41 ± 0.15) and DM (0.24 ± 0.11; F 0.29 ± 0.16) (DM vs. IFG vs. NGT P = 0.001). In contrast, the plasma ubiquinone/ubiquinol ratio increased from NGT (M 0.08 ± 0.07, F 0.06 ± 0.08) to IFG (2.14 ± 1.84, 1.75 ± 1.04) to DM (4.77 ± 4.88, 3.81 ± 3.71) (DM vs. IFG vs. NGT P = 0.001). These differences remained after adjusting for age, body mass index and FPG.

Conclusions  The change in CoQ10 with increasing FPG concentration suggests an increase in oxidative burden, already evident in the prediabetic IFG individuals. This increase in oxidative stress might contribute to the increased risk of vascular disease.
Cortisol—cause and cure for metabolic syndrome?
Authors: Walker B. R.
Published: November 2006

Similarities between the metabolic syndrome and Cushing's syndrome, and reversibility of the features of Cushing's syndrome, suggest that cortisol may contribute to the pathophysiology of both conditions and that reducing cortisol action may provide a novel therapeutic approach in the metabolic syndrome. There is substantial evidence that circulating cortisol concentrations are higher in people with hypertension and glucose intolerance. The basis for this activation of the hypothalamic–pituitary–adrenal axis remains uncertain, but it may be attributable to ‘programming’ effects of events in early life, since it is associated with low birth weight. In obese people, intracellular cortisol levels within adipose tissue are further amplified by increased local regeneration of cortisol by the enzyme 11β‐HSD type 1. In mice, transgenic manipulations of 11β‐HSD1 have potent effects on obesity and associated features of the metabolic syndrome. Promising preclinical data suggest that novel 11β‐HSD1 inhibitors will have a role in lowering intracellular cortisol levels as a treatment for the metabolic syndrome. In addition to their metabolic effects, glucocorticoids act in the blood vessel wall. Pharmacoepidemiological studies suggest that glucocorticoid excess is an independent risk factor for cardiovascular disease. Recent data suggest that 11β‐HSD1 within the blood vessel wall influences vascular remodelling and angiogenesis, for example in the myocardium following coronary artery occlusion. Thus, glucocorticoid signalling provides a potentially tractable system to influence both risk factors for, and the outcome of, Type 2 diabetes and cardiovascular disease.
Hepatocyte nuclear factor‐1 beta mutations cause neonatal diabetes and intrauterine growth retardation: support for a critical role of HNF‐1β in human pancreatic development
Authors: Edghill E. L. , Bingham C. , Slingerland A. S. , Minton J. A. L. , Noordam C. , Ellard S. , Hattersley A. T.
Published: November 2006

Aim  The transcription factor hepatocyte nuclear factor‐1beta (HNF‐1β) is expressed in rodent pancreatic progenitor cells, where it is an important member of the genetic hierarchy that regulates the generation of pancreatic endocrine and exocrine cells. The recent description of an HNF‐1β mutation in a patient with neonatal diabetes suggests that HNF‐1β may also play a key role in human pancreatic B‐cell development. We aimed to investigate the role of HNF‐1β mutations in neonatal diabetes and also the impact of HNF‐1β mutations on fetal growth.

Methods  We sequenced the HNF‐1β gene in 27 patients with neonatal diabetes in whom other known genetic aetiologies had been excluded. Birth weight was investigated in 21 patients with HNF‐1β mutations.

Results  A heterozygous HNF‐1β mutation, S148L, was identified in one patient with neonatal diabetes diagnosed at 17 days, which rapidly resolved only to relapse at 8 years. This patient had pancreatic atrophy, mild exocrine insufficiency and low birth weight (1.83 kg at 40 weeks’ gestation). Intrauterine growth was markedly reduced in patients born to unaffected mothers with a median birth weight of 2.4 kg (range 1.8–3.3) (P = 0.006), median centile weight 3 (0.008–38), and 69% were small for gestational age.

Conclusion  HNF‐1β mutations are a rare cause of neonatal diabetes as well as pancreatic exocrine and endocrine dysfunction. Low birth weight is a common feature of patients with HNF‐1β mutations and is consistent with reduced insulin secretion in utero. These findings support a key role for HNF‐1β in early pancreatic progenitor cells in man.
Peroxisome proliferator‐activated receptor (PPAR) delta genetic polymorphism and its association with insulin resistance index and fasting plasma glucose concentrations in Chinese subjects
Authors: Hu C. , Jia W. , Fang Q. , Zhang R. , Wang C. , Lu J. , Xiang K.
Published: November 2006

Aims  Previous studies have shown that the peroxisome proliferator‐activated receptor delta (PPARD) genetic polymorphism affects cholesterol metabolism in Whites. This association was not observed in a Korean population in a separate study, but this study showed a link between the PPARD polymorphism and body weight and fasting plasma glucose. The purpose of this study was to determine whether polymorphisms of PPARD influence glucose and cholesterol metabolism in Chinese subjects. We investigated the association between the polymorphism (−87T/C) of the human PPARD gene and phenotypes related to body weight, insulin sensitivity, glucose and lipid metabolism in Chinese subjects.

Methods  Unrelated Chinese subjects (n = 663) in Shanghai were studied; 287 had newly diagnosed Type 2 diabetes mellitus and 376 were non‐diabetic control subjects over 40 years old. Clinical parameters were collected and genotypes were determined by polymerase chain reaction‐restriction fragment length polymorphism.

Results  In normal glucose tolerant (NGT) subjects, the C allele carriers had higher fasting plasma glucose concentrations (P = 0.0078) and a lower insulin sensitivity index (ISI) (P = 0.0365). The C allele carriers also showed higher concentrations of low‐density lipoprotein cholesterol (P = 0.0261) and percentage of body fat (P = 0.0357). There was a trend towards higher visceral adiposity in C allele carriers, but the difference was not significant (P = 0.0830). In diabetes patients, similar results were detected for plasma glucose concentrations (fasting plasma glucose P < 0.0001, 2‐h plasma glucose P = 0.0052) and insulin sensitivity (homeostasis model assessment of insulin resistance P = 0.0094; ISI P = 0.0058).

Conclusion  The PPARD−87T/C polymorphism is associated with higher fasting plasma glucose concentrations in both NGT and diabetic subjects, largely due to impaired insulin sensitivity.
Prevalence of and risk factors for extracranial internal carotid artery stenosis in Korean Type 2 diabetic patients
Authors: Park J. H. , Kim W. H. , Kim J. H. , Park T. S. , Baek H. S.
Published: November 2006

Aims  The objectives of this study were to evaluate the prevalence of and risk factors for extracranial internal carotid artery stenosis in Type 2 diabetic patients.

Methods  This study included 406 patients aged 40–79 years with Type 2 diabetes (male 55.4%, female 44.6%). Both carotid arteries of each patient were examined by carotid duplex scanning. The duplex ultrasound criteria based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement method were used for the identification of carotid stenosis.

Results  Extracranial internal carotid artery stenosis ≥ 40% by velocity criteria was detected in 5.2% of the patients. The prevalence of carotid stenosis increased with advancing age: 1.0% at 40–49 years of age, 5.0% at 50–59 years, 7.3% at 60–69 years and 9.5% at 70–79 years. The degree of stenosis was > 70% in 42.9% of patients with stenosis, Bilateral stenosis was detected in 14% of patients. Of the patients with ≥ 40% carotid stenosis, 33% had a decreased ankle‐brachial index, 38% had a previous history of stroke, and only one patient (5%) had a documented history of coronary artery disease. Multivariate analysis, including variables determined to be significantly different by univariate analysis between patients with or without ≥ 40% stenosis, indicated that age, systolic blood pressure and high‐density lipoprotein (HDL)‐cholesterol (inverse correlation) were independent risk factors associated with carotid stenosis.

Conclusions  Carotid duplex scanning is a useful strategy in identifying carotid stenosis in older Type 2 diabetic patients with high systolic blood pressure, or low levels of HDL cholesterol. The early identification and subsequent appropriate management of carotid stenosis, particularly in this group of patients, may facilitate efforts to reduce the incidence of macrovascular complications.
Engineering of a sialic acid synthesis pathway in transgenic plants by expression of bacterial Neu5Ac‐synthesizing enzymes
Authors: Paccalet Thomas , Bardor Muriel , Rihouey Christophe , Delmas Frédéric , Chevalier Christian , D’Aoust Marc‐André , Faye Loïc , Vézina Louis , Gomord Véronique , Lerouge Patrice
Published: November 2006

Plants are a low‐cost and contamination‐free factory for the production of recombinant pharmaceutical proteins. However, plant‐made pharmaceuticals differ from their mammalian homologues by the structure of their N‐linked glycans. For instance, most mammalian glycoproteins harbour terminal sialic acids that control their half‐life in the bloodstream. The absence of the whole sialylation machinery in plants is of major concern as non‐sialylated plant‐made pharmaceuticals may not perform at their full potential in humans, because of their removal from the circulation through the involvement of hepatic cell receptors. In this context, we have investigated the synthesis of N‐acetylneuraminic acid (Neu5Ac) in the cytosol of plants by either the re‐routing of the endogenous 3‐deoxy‐d‐manno‐2‐octulosonic acid (Kdo) biosynthetic pathway or the expression of microbial Neu5Ac‐synthesizing enzymes. In this paper, we demonstrate that the plant Kdo‐8P synthase is not able to use N‐acetyl d‐mannosamine as a substrate, and thus re‐routing of the Kdo pathway for the synthesis of Neu5Ac is not possible. Consequently, we expressed genes encoding Neu5Ac lyase from Escherichia coli and Neu5Ac synthase (neuB2) from Campylobacter jejuni in plants. These resulted in the production of functional enzymes in the cytosol, which in turn can catalyse the synthesis of Neu5Ac in vitro. Experiments were carried out on two models, Bright Yellow 2 (BY2) tobacco cells and Medicago sativa (alfalfa), the perennial legume crop.
3. A Partial Independence Item Response Model for Surveys with Filter Questions
Authors: Reardon Sean F. , Raudenbush Stephen W.
Published: November 2006

In many surveys, responses to earlier questions determine whether later questions are asked. The probability of an affirmative response to a given item is therefore nonzero only if the participant responded affirmatively to some set of logically prior items, known as “filter items.” In such surveys, the usual conditional independence assumption of standard item response models fails. A weaker “partial independence” assumption may hold, however, if an individual's responses to different items are independent conditional on the item parameters, the individual's latent trait, and the participant's affirmative responses to each of a set of filter items. In this paper, we propose an item response model for such “partially independent” item response data. We model such item response patterns as a function of a person-specific latent trait and a set of item parameters. Our model can be seen as a generalized hybrid of a discrete-time hazard model and a Rasch model. The proposed procedure yields estimates of (1) person-specific, interval-scale measures of a latent trait (or traits), along with person-specific standard errors of measurement; (2) conditional and marginal item severities for each item in a protocol; (3) person-specific conditional and marginal probabilities of an affirmative response to each item in a protocol; and (4) item information and total survey information. In addition, we show here how to investigate and test alternative conceptions of the dimensionality of the latent trait(s) being measured. Finally, we compare our procedure with a simpler alternative approach to summarizing data of this type.
4. The Safety Dance: Confronting Harassment, Intimidation, and Violence in the Field
Authors: Sharp Gwen , Kremer Emily
Published: November 2006

This paper discusses how gender dynamics may put female researchers at risk of harassment or even violence from participants, research assistants, or bystanders when conducting fieldwork. Based on a review of the existing literature on fieldwork safety, as well as the authors' own experiences interviewing male participants, the authors argue that attention to protecting subjects of research has led the social science community to largely ignore the possibility that in some cases, researchers themselves may be at risk. The paper concludes with suggested strategies for increasing researcher safety during data collection, as well as a call for issues of fieldwork safety to be more openly discussed by supervisors, professors, advisors, and others who guide novice researchers through the fieldwork process.
Eleven microsatellite loci isolated from the banded wren (Thryothorus pleurostictus)
Authors: BRAR R. K. , SCHOENLE L. A. , STENZLER L. M. , HALL M. L. , VEHRENCAMP S. L. , LOVETTE I. J.
Published: November 2006

We describe 11 microsatellite loci isolated from the banded wren (Thryothorus pleurostictus), a Neotropical species for which understanding the genetic mating system is important for testing questions about the species’ unusual vocal behaviour. Screening of these loci revealed extremely low allelic variation in a Costa Rican population. Allelic variation at these and other previously developed loci is substantially higher in two other wren species, the southern house wren (Troglodytes aedon bonariae) and rufous‐and‐white wren (Thryothorus rufalbus), suggesting that the low allelic diversity in the banded wren results from demographic bottlenecks rather than locus‐sampling artefacts.
Isolation of polymorphic microsatellite loci from Eurasian woodcock (Scolopax rusticola) and their cross‐utility in related species
Authors: CARDIA P. , FERRERO M. E. , GONÇALVES D. , DÁVILA J. A. , FERRAND N.
Published: November 2006

We isolated one trinucleotide and seven tetranucleotide microsatellite loci for the Eurasian woodcock (Scolopax rusticola). We describe polymerase chain reaction conditions and primers for the successful amplification of these loci and report the results obtained from their use in 42 specimens from two populations in Europe. The number of alleles per locus ranged from three to 15, observed heterozygosity was comprised between 0.11 and 1.00 and expected heterozygosity ranged between 0.10 and 0.91. Cross‐specific amplification experiments highlighted the potential usefulness of these molecular markers for the study of three related scolopacid waders.
Development of 19 microsatellite loci for Swainson's hawks (Buteo swainsoni) and other buteos
Authors: HULL JOSHUA M. , TUFTS DANIELLE , TOPINKA J. RICK , MAY BERNIE , ERNEST HOLLY B.
Published: November 2006

We developed 26 Swainson's hawk (Buteo swainsoni) microsatellite primers from CA, AAT, CATC and GAGAA enriched genomic libraries. Primers were tested in 357 Swainson's hawks from western North America as well as seven other Buteo species. These markers will have broad application in investigations of Buteo population structure and genetic diversity.
Incorporating spatial autocorrelation may invert observed patterns
Authors: Kühn Ingolf
Published: November 2006

Though still often neglected, spatial autocorrelation can be a serious issue in ecology because the presence of spatial autocorrelation may alter the parameter estimates and error probabilities of linear models. Here I re‐analysed data from a previous study on the relationship between plant species richness and environmental correlates in Germany. While there was a positive relationship between native plant species richness and an altitudinal gradient when ignoring the presence of spatial autocorrelation, the use of a spatial simultaneous liner error model revealed a negative relationship. This most dramatic effect where the observed pattern was inverted may be explained by the environmental situation in Germany. There the highest altitudes are in the south and the lowlands in the north that result in some locally or regionally inverted patterns of the large‐scale environmental gradients from the equator to the north. This study therefore shows the necessity to consider spatial autocorrelation in spatial analyses.
Seasonal reversals of upland‐riparian diversity gradients in the Sonoran Desert
Authors: Stromberg J. C.
Published: November 2006

Flood disturbance and water resource availability vary sharply over time and space along arid‐region rivers and can interact in complex fashion to shape diversity patterns. Plant diversity showed spatial patterning along a topogradient from the floodplain of the San Pedro River (Arizona, USA) to the arid upland, but the patterns shifted temporally as the suite of limiting factors changed. During two of three sampling times, spatial diversity patterns were shaped primarily by gradients of water availability, the regional limiting factor. In the summer dry season, microscale diversity (species richness per 1 m2) and mesoscale diversity (cumulative species and functional types in 20, 1‐m2 plots) of herbaceous plants decreased along the topogradient from floodplain to upland, reflecting the greater water availability on the low surfaces. During a summer wet season with moderate rains and flooding, diversity increased in all hydrogeomorphic zones (floodplain, terrace, upland), but the spatial pattern along the topogradient persisted. Following a very wet winter, patterns along the topogradient reversed: scour from large floods limited diversity on the floodplain and competitive exclusion limited the diversity on undisturbed river terrace, while abundant rains allowed for high microscale diversity in the upland. Disturbance and resource availability thus interacted to influence plant species diversity in a fashion consistent with the dynamic‐equilibrium model of species diversity. In contrast to the microscale patterns, mesoscale diversity of species and functional types remained high in the floodplain during all sampling times, with 58% more plant species and 90% more functional types sampled in low floodplain than arid upland for the year as a whole. Species with a wide range of moisture and temperature affinities were present in the floodplain, and seasonal turnover of species was high in this zone. The floodplain zone of a perennial to intermittent‐flow river thus had greater plant diversity than arid Sonoran Desert upland, as measured at temporal scales that capture seasonal variance in resource and disturbance pulses and at spatial scales that capture the environmental heterogeneity of floodplains. Although periodically limited by intense flood disturbance, diversity remains high in the floodplain because of the combination of moderate resource levels (groundwater, seasonal flood water) and persistent effects of flood disturbance (high spatial heterogeneity, absence of competitive exclusion), in concert with the same climatic factors that produce seasonally high diversity in the region (temporally variable pulses of rainfall).
Cyanobacterial calcification, carbon dioxide concentrating mechanisms, and Proterozoic–Cambrian changes in atmospheric composition
Authors: RIDING R.
Published: November 2006

Photosynthetic uptake of inorganic carbon can raise the pH adjacent to cyanobacterial cells, promoting CaCO3 precipitation. This effect is enhanced by CO2 concentrating mechanisms that actively transport into cells for carbon fixation. CO2 concentrating mechanisms presumably developed in response to atmospheric decrease in CO2 and increase in O2 over geological timescales. In present‐day cyanobacteria, CO2 concentrating mechanisms are induced when the atmospheric partial pressure of CO2 (pCO2) falls below ∼0.4%. Reduction in pCO2 during the Proterozoic may have had two successive effects on cyanobacterial calcification. First, fall in pCO2 below ∼1% (33 times present atmospheric level, PAL) resulted in lower dissolved inorganic carbon (DIC) concentrations that reduced pH buffering sufficiently for isolated CaCO3 crystals to begin to nucleate adjacent to cyanobacterial cells. As a result, blooms of planktic cyanobacteria induced precipitated ‘whitings’ of carbonate mud in the water column whose sedimentary accumulation began to dominate carbonate platforms ∼1400–1300 Ma. Second, fall in pCO2 below ∼0.4% (10 PAL) induced CO2‐concentrating mechanisms that further increased pH rise adjacent to cells and promoted in vivo cyanobacterial sheath calcification. Crossing of this second threshold is indicated in the fossil record by the appearance of Girvanella 750–700 Ma. Coeval acquisition of CO2 concentrating mechanisms by planktic cyanobacteria further stimulated whiting production. These inferences, that pCO2 fell below ∼1%∼1400–1300 Ma and below ∼0.4% 750–700 Ma, are consistent with empirical and modelled palaeo‐atmosphere estimates. Development of CO2 concentrating mechanisms was probably temporarily slowed by global cooling ∼700–570 Ma that favoured diffusive entry of CO2 into cells. Lower levels of temperature and DIC at this time would have reduced seawater carbonate saturation state, also hindering cyanobacterial calcification. It is suggested that as Earth emerged from ‘Snowball’ glaciations in the late Neoproterozoic, global warming and O2 rise reactivated the development of CO2 concentrating mechanisms. At the same time, rising levels of temperature, calcium ions and DIC increased seawater carbonate saturation state, stimulating widespread cyanobacterial in vivo sheath calcification in the Early Cambrian. This biocalcification event promoted rapid widespread development of calcified cyanobacterial reefs and transformed benthic microbial carbonate fabrics.