bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate binding in quinoprotein ethanol dehydrogenase from
Pseudomonas aeruginosa
studied by electron-nuclear double resonance
Authors: Kay Christopher W. M. , Mennenga Bina , Görisch Helmut , Bittl Robert
Published: March 2006

Binding of methanol to the quinoprotein ethanol dehydrogenase from
Pseudomonas aeruginosa
has been studied by pulsed electron-nuclear double resonance at 9 GHz. Shifts in the hyperfine couplings of the pyrroloquinoline quinone radical provide direct evidence for a change in the environment of the cofactor when substrate is present. By performing experiments with deuteriated methanol, we confirmed that methanol was the cause of the effect. Density functional theory calculations show that these shifts can be understood if a water molecule, which is often found in x-ray structures of the active site of quinoprotein alcohol dehydrogenases, is displaced by the substrate. The difference between the binding of water and methanol is that the water molecule forms a hydrogen bond to O5 of pyrroloquinoline quinone, which the methanol, by virtue of its methyl group, does not. The results support the proposal that aspartate rather than glutamate is the catalytically active base for a hydride transfer mechanism in quinoprotein alcohol dehydrogenases.
Na
+
/H
+
exchanger type 1 is a receptor for pathogenic subgroup J avian leukosis virus
Authors: Chai Ning , Bates Paul
Published: March 2006

Subgroup J avian leukosis virus (ALV-J) is a recently identified avian oncogenic retrovirus responsible for severe economic losses worldwide. In contrast with the other ALV subgroups, ALV-J predominantly induces myeloid leukosis in meat-type chickens. Despite significant homology with the other ALV subgroups across most of the genome, the envelope protein of ALV-J (EnvJ) shares low homology with the others. Pathogenicity and myeloid leukosis induction map to the
env
gene of ALV-J. A chimeric protein composed of the surface domain of EnvJ fused to the constant region of a rabbit IgG and mass spectrometry were used to identify the chicken Na
+
/H
+
exchanger type 1 (chNHE1) as a binding protein for ALV-J. Flow cytometry analysis and coprecipitation experiments demonstrated a specific interaction between EnvJ and chNHE1. When introduced into nonpermissive human 293T cells and quail QT6 cells, chNHE1 conferred susceptibility to EnvJ-mediated infection. Furthermore, 293T cells expressing chNHE1 fused with 293T cells expressing EnvJ in a low-pH-dependent manner. Together, these data identify chNHE1 as a cellular receptor for the highly pathogenic ALV-J.
Apolipoprotein E4: A causative factor and therapeutic target in neuropathology, including Alzheimer’s disease
Authors: Mahley Robert W. , Weisgraber Karl H. , Huang Yadong
Published: March 2006

The premise of this review is that apolipoprotein (apo) E4 is much more than a contributing factor to neurodegeneration. ApoE has critical functions in redistributing lipids among CNS cells for normal lipid homeostasis, repairing injured neurons, maintaining synapto-dendritic connections, and scavenging toxins. In multiple pathways affecting neuropathology, including Alzheimer’s disease, apoE acts directly or in concert with age, head injury, oxidative stress, ischemia, inflammation, and excess amyloid β peptide production to cause neurological disorders, accelerating progression, altering prognosis, or lowering age of onset. We envision that unique structural features of apoE4 are responsible for apoE4-associated neuropathology. Although the structures of apoE2, apoE3, and apoE4 are in dynamic equilibrium, apoE4, which is detrimental in a variety of neurological disorders, is more likely to assume a pathological conformation. Importantly, apoE4 displays domain interaction (an interaction between the N- and C-terminal domains of the protein that results in a compact structure) and molten globule formation (the formation of stable, reactive intermediates with potentially pathological activities). In response to CNS stress or injury, neurons can synthesize apoE. ApoE4 uniquely undergoes neuron-specific proteolysis, resulting in bioactive toxic fragments that enter the cytosol, alter the cytoskeleton, disrupt mitochondrial energy balance, and cause cell death. Our findings suggest potential therapeutic strategies, including the use of “structure correctors” to convert apoE4 to an “apoE3-like” molecule, protease inhibitors to prevent the generation of toxic apoE4 fragments, and “mitochondrial protectors” to prevent cellular energy disruption.
Insights into transcriptional regulation and σ competition from an equilibrium model of RNA polymerase binding to DNA
Authors: Grigorova Irina L. , Phleger Naum J. , Mutalik Vivek K. , Gross Carol A.
Published: March 2006

To explore scenarios that permit transcription regulation by activator recruitment of RNA polymerase and σ competition
in vivo
, we used an equilibrium model of RNA polymerase binding to DNA constrained by the values of total RNA polymerase (E) and σ
70
per cell measured in this work. Our numbers of E and σ
70
per cell, which are consistent with most of the primary data in the literature, suggest that
in vivo
(
i
) only a minor fraction of RNA polymerase (<20%) is involved in elongation and (
ii
) σ
70
is in excess of total E. Modeling the partitioning of RNA polymerase between promoters, nonspecific DNA binding sites, and the cytoplasm suggested that even weak promoters will be saturated with Eσ
70
in vivo
unless nonspecific DNA binding by Eσ
70
is rather significant. In addition, the model predicted that σs compete for binding to E only when their total number exceeds the total amount of RNA polymerase (excluding that involved in elongation) and that weak promoters will be preferentially subjected to σ competition.
Bottleneck-mediated quasispecies restriction during spread of an RNA virus from inoculation site to brain
Authors: Pfeiffer Julie K. , Kirkegaard Karla
Published: March 2006

The amplification of RNA viruses such as poliovirus is associated with high error rates, and the resulting diversity likely facilitates viral survival within an infected host. However, within individual tissues of infected hosts, there may be barriers to viral spread that limit genome sampling. We tested whether poliovirus population diversity was maintained during viral spread to the brain of poliovirus receptor-expressing mice. Each of four restriction enzyme site-tagged viruses was shown to be able to replicate in the mouse brain. However, when infection was initiated by i.m., i.v., or i.p. routes, only a subset of the members of the injected pool was detectable in the brain. This jackpot effect was the result of a bottleneck in viral transit from the inoculation site to the brain. The bottleneck was difficult to overcome, requiring a 10
7
increase in viral inoculum to allow representation of all or most members of the infecting pool. Therefore, the bottleneck is not likely to be a physical barrier but an antiviral state induced by a founder virus. We suggest that the innate immune response can limit viral pathogenicity by limiting the number and therefore the diversity of viruses during spread to vulnerable tissues.
Evolution of cis elements in the differential expression of two
Hoxa2
coparalogous genes in pufferfish (
Takifugu rubripes
)
Authors: Tümpel Stefan , Cambronero Francisco , Wiedemann Leanne M. , Krumlauf Robb
Published: March 2006

Sequence divergence in cis-regulatory elements is an important mechanism contributing to functional diversity of genes during evolution. Gene duplication and divergence provide an opportunity for selectively preserving initial functions and evolving new activities. Many vertebrates have 39
Hox
genes organized into four clusters (
Hoxa
–
Hoxd
); however, some ray-finned fishes have extra
Hox
clusters. There is a single
Hoxa2
gene in most vertebrates, whereas fugu (
Takifugu rubripes
) and medaka (
Oryzias latipes
) have two coparalogous genes [
Hoxa2
(
a
) and
Hoxa2
(
b
)]. In the hindbrain, both genes are expressed in rhombomere (r) 2, but only
Hoxa2
(
b
) is expressed in r3, r4, and r5. Multiple regulatory modules directing segmental expression of chicken and mouse
Hoxa2
genes have been identified, and each module is composed of a series of discrete elements. We used these modules to investigate the basis of differential expression of duplicated
Hoxa2
genes, as a model for understanding the divergence of cis-regulatory elements. Therefore, we cloned putative regulatory regions of the fugu and medaka
Hoxa2
(
a
) and -(
b
) genes and assayed their activity. We found that these modules direct reporter expression in a chicken assay, in a manner corresponding to their endogenous expression pattern in fugu. Although sequence comparisons reveal many differences between the two coparalogous genes, specific subtle changes in seven cis elements of the
Hoxa2
(
a
) gene restore segmental regulatory activity. Therefore, drift in subsets of the elements in the regulatory modules is responsible for the differential expression of the two coparalogous genes, thus providing insight into the evolution of cis elements.
A high-resolution map of transcription in the yeast genome
Authors: David Lior , Huber Wolfgang , Granovskaia Marina , Toedling Joern , Palm Curtis J. , Bofkin Lee , Jones Ted , Davis Ronald W. , Steinmetz Lars M.
Published: March 2006

There is abundant transcription from eukaryotic genomes unaccounted for by protein coding genes. A high-resolution genome-wide survey of transcription in a well annotated genome will help relate transcriptional complexity to function. By quantifying RNA expression on both strands of the complete genome of
Saccharomyces cerevisiae
using a high-density oligonucleotide tiling array, this study identifies the boundary, structure, and level of coding and noncoding transcripts. A total of 85% of the genome is expressed in rich media. Apart from expected transcripts, we found operon-like transcripts, transcripts from neighboring genes not separated by intergenic regions, and genes with complex transcriptional architecture where different parts of the same gene are expressed at different levels. We mapped the positions of 3′ and 5′ UTRs of coding genes and identified hundreds of RNA transcripts distinct from annotated genes. These nonannotated transcripts, on average, have lower sequence conservation and lower rates of deletion phenotype than protein coding genes. Many other transcripts overlap known genes in antisense orientation, and for these pairs global correlations were discovered: UTR lengths correlated with gene function, localization, and requirements for regulation; antisense transcripts overlapped 3’ UTRs more than 5’ UTRs; UTRs with overlapping antisense tended to be longer; and the presence of antisense associated with gene function. These findings may suggest a regulatory role of antisense transcription in
S. cerevisiae
. Moreover, the data show that even this well studied genome has transcriptional complexity far beyond current annotation.
NifB-dependent
in vitro
synthesis of the iron–molybdenum cofactor of nitrogenase
Authors: Curatti Leonardo , Ludden Paul W. , Rubio Luis M.
Published: March 2006

Biological nitrogen fixation, an essential process of the biogeochemical nitrogen cycle that supports life on Earth, is catalyzed by the nitrogenase enzyme. The nitrogenase active site contains an iron and molybdenum cofactor (FeMo-co) composed of 7Fe-9S-Mo-homocitrate and one not-yet-identified atom, which probably is the most complex [Fe–S] cluster in nature. Here, we show the
in vitro
synthesis of FeMo-co from its simple constituents, Fe, S, Mo, and homocitrate. The
in vitro
FeMo-co synthesis requires purified NifB and depends on
S
-adenosylmethionine, indicating that radical chemistry is required during FeMo-co assembly.
FRA1 is a determinant for the difference in RAS-induced transformation between human and rat fibroblasts
Authors: Kakumoto Kyoko , Sasai Ken , Sukezane Taiko , Oneyama Chitose , Ishimaru Satoshi , Shibutani Kana , Mizushima Hiroto , Mekada Eisuke , Hanafusa Hidesaburo , Akagi Tsuyoshi
Published: March 2006

Human diploid fibroblasts (HDF) immortalized by hTERT and simian virus 40 (SV40) early region (ER) exhibit a limited degree of transformation upon the expression of activated H-RAS (H-RAS V12) compared with rat embryonic fibroblasts (REF) immortalized by SV40 ER. Here, we identified FRA1 as a determinant for this difference in RAS-induced transformation. FRA1 was not induced by H-RAS V12 in the immortalized HDF, in contrast to its marked accumulation in the immortalized REF. Ectopic expression of FRA1 significantly enhanced anchorage-independent growth of various HDF expressing hTERT, SV40 ER, and H-RAS V12. More importantly, FRA1 could induce anchorage-independent growth as well as nude mice tumor formation of the immortalized HDF in the absence of H-RAS V12. The results of an
in vitro
kinase assay clearly showed that the RAS-induced extracellular signal-regulated kinase (ERK) activation, which is responsible for FRA1 induction, was markedly attenuated in the HDF compared with that in the REF, despite no obvious differences in the phosphorylation status of ERK between the species. Our results strongly suggest that HDF negatively regulate the mitogen-activated protein kinase kinase (MEK)/ERK pathway more efficiently than REF, and consequently express less malignant phenotypes in response to H-RAS V12.
Specific T-type calcium channel isoforms are associated with distinct burst phenotypes in deep cerebellar nuclear neurons
Authors: Molineux Michael L. , McRory John E. , McKay Bruce E. , Hamid Jawed , Mehaffey W. Hamish , Rehak Renata , Snutch Terrance P. , Zamponi Gerald W. , Turner Ray W.
Published: March 2006

T-type calcium channels are thought to transform neuronal output to a burst mode by generating low voltage-activated (LVA) calcium currents and rebound burst discharge. In this study we assess the expression pattern of the three different T-type channel isoforms (Ca
v
3.1, Ca
v
3.2, and Ca
v
3.3) in cerebellar neurons and focus on their potential role in generating LVA spikes and rebound discharge in deep cerebellar nuclear (DCN) neurons. We detected expression of one or more Ca
v
3 channel isoforms in a wide range of cerebellar neurons and selective expression of different isoforms in DCN cells. We further identify two classes of large-diameter DCN neurons that exhibit either a strong or weak capability for rebound discharge, despite the ability to generate LVA spikes when calcium currents are pharmacologically isolated. By correlating the Ca
v
3 channel expression pattern with the electrophysiological profile of identified DCN cells, we show that Ca
v
3.1 channels are expressed in isolation in DCN-burst cells, whereas Ca
v
3.3 is expressed in DCN-weak burst cells. Ca
v
3.1-expressing DCN cells correspond to excitatory or GABAergic neurons, whereas Ca
v
3.3-expressing cells are non-GABAergic. The Ca
v
3 class of LVA calcium channels is thus expressed in specific combinations in a wide range of cerebellar neurons but contributes to rebound burst discharge in only a select number of cell classes.
Integrin-driven actin polymerization consolidates long-term potentiation
Authors: Kramár Enikö A. , Lin Bin , Rex Christopher S. , Gall Christine M. , Lynch Gary
Published: March 2006

Long-term potentiation (LTP), like memory, becomes progressively more resistant to disruption with time after its formation. Here we show that threshold conditions for inducing LTP cause a rapid, long-lasting increase in polymerized filamentous actin in dendritic spines of adult hippocampus. Two independent manipulations that reverse LTP disrupted this effect when applied shortly after induction but not 30 min later. Function-blocking antibodies to β1 family integrins selectively eliminated both actin polymerization and stabilization of LTP. We propose that the initial stages of consolidation involve integrin-driven events common to cells engaged in activities that require rapid morphological changes.
Control of energy balance in relation to energy intake and energy expenditure in animals and man: an ecological perspective
Authors: Stubbs R. J. , Tolkamp B. J.
Published: March 2006

In this paper, we consider the control of energy balance in animals and man. We argue that patterns of mammalian feeding have evolved to control energy balance in uncertain environments. It is, therefore, expected that, under sedentary conditions in which the diet is rich in nutrients and abundantly available, animals and man will overeat. This suggests that no physiological defects are needed to induce overweight and ultimately obesity in man. Several considerations arise from these observations. The time period over which energy balance is controlled is far longer than allowed by most experiments. Physiological models of energy balance control often treat excess energy intake as a defect of regulation; ecological models view the same behaviour as part of normal energy balance control in environments where resources are uncertain. We apply these considerations to common patterns of human and animal feeding. We believe that the ecological perspective gives a more accurate explanation for the functionality of excess fat and the need to defend nutrient balance and avoid gross imbalances, as well as explaining hyperphagia in the face of plenty. By emphasising the common features of energy balance control in different mammalian species, the importance of changes in behaviour to accommodate changes in the environment becomes apparent. This also opens up possibilities for the control of body weight and the treatment of obesity in man.
Dietary patterns are associated with sexual maturation in Korean children
Authors: Li Shan Ji , Paik Hee Young , Joung Hyojee
Published: March 2006

The purpose of this study was to investigate the association between dietary patterns and sexual maturation among Korean children. A cross-sectional study was conducted in 422 boys and 365 girls aged 9–12 years living in Seoul, Korea. Three-day food records were obtained, and pubertal stages were determined with a questionnaire using Tanner stages. Body fat was measured by bioelectrical impedance analysis, and bone mass content at the right calcaneus was measured by portable dual-emission X-ray absorptiometry. Exploratory factor analysis with a Varimax rotation was applied to identify dietary patterns using twenty-four food groups. Four distinct dietary patterns – ‘rice and Kimchi’, ‘shellfish and processed meat’, ‘pizza and drinks’ and ‘milk and cereal’ – were obtained. Twenty-six per cent (24% stage 2, 2% stage 3) of boys had genital development, and 79% (63% stage 2, 16% stage 3) of girls showed breast development. In boys, genital development was weakly positively associated with ‘shellfish and processed meat’ dietary factor scores (odds ratio 1·65, CI 0·95, 2·89,pfor trend 0·07) after adjusting for confounders. In girls, breast development was significantly positively associated with the factor score of ‘shellfish and processed meat’ (odds ratio 1·88, CI 1·08, 3·26,pfor trend 0·05). These results suggest that dietary patterns were related to body composition and sexual maturation among the Korean children. Further investigations are needed to identify components of the foods consumed in high amounts in these patterns and how they are related to sexual maturation.
Trans-11–18: 1 is effectively δ9-desaturated compared withTrans-12–18: 1 in humans
Authors: Kuhnt Katrin , Kraft Jana , Moeckel Peter , Jahreis Gerhard
Published: March 2006

The aim of this human intervention study was to evaluate the Δ9-desaturation oftrans-11–18:1 (trans-vaccenic acid;tVA) tocis-9,trans-11–18:2 (c9,t11 conjugated linoleic acid; CLA) and oftrans-12–18:1 (t12) tocis-9,trans-12–18:2 after a short-term (7d) and a long-term (42d) supplementation period. The conversion rates of bothtrans-18:1 isomers were estimated by lipid analysis of serum and red blood cell membranes (RBCM). Subjects started with a 2-week adaptation period without supplements. During the 42d intervention period, the diet of the test group was supplemented with 3g/d oftVA and 3g/d oft12. The diet of the control group was supplemented with a control oil. SerumtVA andt12 levels in the test group increased by fivefold and ninefold after 7d, respectively, and by eight- and 12-fold after 42d, respectively, when compared with the adaptation period (p≤0·002). The serumc9,t11CLA levels increased by 1·7- and 2·0-fold after 7d and 42d, respectively (p≤0·001). After 42d, the test group's RBCMc9,t11CLA content was elevated by 20% (p=0·021), whereas in the control group it was decreased by 50% (p=0·002). The conversion rate oftVA was estimated at 24% by serum and 19% by RBCM. No increase inc9,t12–18:2 was observed in the serum and RBCM, and thus no conversion oft12 could be determined. In conclusion, the endogenous conversion of dietarytVA toc9,t11CLA contributes approximately one quarter to the human CLA pool and should be considered when determining the CLA supply.
Protein expression ofpectoralis majormuscle in chickens in response to dietary methionine status
Authors: Corzo A. , Kidd M. T. , Dozier W. A. , Shack L. A. , Burgess S. C.
Published: March 2006

The present study evaluated the effect of dietary methionine on breast-meat accretion and protein expression in skeletal muscle of broiler chickensin vivo. All broilers received a common pre-test diet up to 21d of age, and were subsequently fed either a methionine-deficient (MD) or -adequate (MA) diet (3·1V. 4·5g/kg diet) from age 21 to 42d. Dietary cystine levels were 3·7V. 3·6g/kg diet for the MD and MA diet, respectively. Detrimental effects on carcass yield (P=0·004), abdominal fat percentage (P=0·001), and breast-meat weight (P=0·001), yield (P=0·001), and uniformity (P=0·002) were observed and validated in birds fed MD diets. Via tandem MS, a total of 190 individual proteins were identified frompectoralis major(PM) muscle tissue. From the former composite, peptides from three proteins were observed to be present exclusively in breast muscle from those chickens fed the MD diet (pyruvate kinase, myosin alkali light chain-1, ribosomal-protein-L-29). No proteins were observed to be uniquely expressed in chickens fed MA diets. Research is warranted to further explore the possibility of the proteins pyruate kinase, myosin alkali light chain-1, or ribosomal protein L-29, as potential biological indicators of differences in protein expression of PM of chickens in response to a dietary methionine deficiency.
Maternal intake of antioxidant vitamins in pregnancy in relation to maternal and fetal plasma levels at delivery
Authors: Scaife Alison R. , McNeill Geraldine , Campbell Doris M. , Martindale Sheelagh , Devereux Graham , Seaton Anthony
Published: March 2006

The aim of the present study was to test the hypothesis that maternal intake of antioxidant vitamins is associated with maternal and cord plasma levels at delivery. Women were recruited in early pregnancy in Aberdeen Maternity Hospital and habitual diet during pregnancy was assessed by a food-frequency questionnaire mailed at 34 weeks gestation. Blood samples were taken at recruitment (n1149) and maternal (n1149) and cord blood samples (n747) taken at delivery for analyses of vitamins A, C, E and β-carotene. Maternal plasma levels of vitamin E and β-carotene at delivery were significantly higher than levels in early pregnancy while levels of vitamins A and C were significantly lower. Positive correlations were observed for maternal levels of all the vitamins between early pregnancy and delivery. At delivery, maternal plasma concentrations of vitamins A, E and β-carotene were significantly higher than cord levels, while maternal levels of vitamin C were significantly lower. There were significant correlations between maternal and cord plasma concentrations for β-carotene and vitamin C but not for vitamins A or E. Maternal dietary intakes were positively correlated with maternal plasma levels of vitamins C, E and β-carotene in early pregnancy, with maternal plasma levels of β-carotene and vitamin C at delivery and with cord plasma levels of β-carotene and vitamin C. The results from the present study show that, in this population, maternal diet influences cord plasma levels of β-carotene and vitamin C, but not vitamins A and E.
Microalgal docosahexaenoic acid decreases plasma triacylglycerol in normolipidaemic vegetarians: a randomised trial
Authors: Geppert Julia , Kraft Veronika , Demmelmair Hans , Koletzko Berthold
Published: March 2006

Triacylglycerol (TG) lowering effects ofn−3 long-chain PUFA (n−3 LCPUFA) have been repeatedly demonstrated, but studies investigating the individual effects of EPA or DHA on plasma TG and lipoproteins in man are rare. The effects of a new DHA-rich, almost EPA-free microalgae oil (Ulkeniasp.) on plasma lipids and several safety parameters were investigated in a double-blind, placebo-controlled, parallel design intervention study. Normolipidaemic vegetarians (eighty-seven females, twenty-seven males) consumed daily microalgae oil (0·94g DHA/d) or olive oil (as placebo) for 8 weeks. DHA supplementation decreased plasma TG by 23% from 1·08 (sem 0·07) to 0·83 (sem 0·04) mmol/l (p<0·001). Absolute TG decreases after DHA supplementation were inversely correlated to baseline TG concentrations (r−0·627,p<0·001). Plasma total, LDL and HDL cholesterol increased significantly in the DHA group, resulting in lower TG:HDL cholesterol and unchanged LDL:HDL and total cholesterol:HDL cholesterol ratios. The intake of DHA-rich microalgae oil did not result in any physiologically relevant changes of safety and haemostatic factors. In conclusion, DHA-rich oil from microalgaeUlkeniasp. was well tolerated and can be considered a suitable vegetarian source ofn−3 LCPUFA. Although DHA supplementation improved some CHD risk factors (plasma TG, TG:HDL cholesterol ratio), LDL cholesterol increased. Therefore, the overall effects of this intervention on CHD risk deserve further investigation.
Neonatal leptin treatment programmes leptin hypothalamic resistance and intermediary metabolic parameters in adult rat
Authors: Toste Fabiane Pereira , de Moura Egberto Gaspar , Lisboa Patrícia Cristina , Fagundes Aline Teixeira , de Oliveira Elaine , Passos Magna Cottini Fonseca
Published: March 2006

We previously showed that neonatal leptin treatment programmes higher body weight and food intake in adult rats. Here we investigate whether leptin treatment during lactation affects the anorectic effect of leptin on adult rats and their hypothalamic leptin receptors (OB-Rb) and whether those changes could have consequences on intermediary metabolism. When the offspring were born, pups were divided into two groups: the Lep group, injected daily with leptin (8μg/100g body weight, subcutaneously) for the first 10d of lactation, and the control group, injected daily with saline. After weaning (day 21), body weight and food intake were monitored until the rats were 150d old. Food intake was higher in the Lep group (approximately 14%,p<0·05) from day 133 onwards, and body weight was higher (approximately 10%,p<0·05) from day 69 onwards, compared with the control group. At 150d of age, the rats were tested for food intake in response to either leptin (05mg/kg body weight intraperitoneally; groups CL and LepL) or saline (groups CSal and LepSal). The CL group showed a decrease in food intake, but no response was observed in the LepL group, suggesting leptin resistance. The Lep group demonstrated a decrease in OB-Rb expression (−40%p<0·05), hyperleptinaemia (+78%,p<0·05), hyperinsulinaemia (+100%,p<0·02), hypertriacylglycerolaemia (+17%,p<0·05) and a higher protein content in the body (+16%,p<0·05) without changes in fat mass and glycaemia. We conclude that neonatal leptin treatment programmes both hyperleptinaemia and hyperinsulinaemia in adulthood, which leads to leptin resistance by reducing the expression of the hypothalamic leptin receptor.
Amino acid composition of TopCross high-oil maize grain
Authors: Thomison P. R. , Barker D. J. , Geyer A. B. , Lotz L. D. , Siegrist H. J. , Dobbels T. L.
Published: March 2006

Increased amino acid content in high-oil maize (Zea mays L.) grain may add further value to its use in livestock rations, especially if this enhanced amino acid content is consistent across varying growing conditions. Most high-oil maize (HOM) grown in the USA utilizes the TopCross system which involves planting a blend (TC Blend) of two types of maize. Field experiments and on-farm studies were conducted in 1997 and 1998 to compare the amino acid profile of grain from HOM TC Blends with that of their normal-oil maize (NOM) counterparts across a range of production environments in Ohio. In 1997, the composition of four amino acids (lysine, methionine, glycine and arginine) was significantly higher in HOM compared to NOM grain. In 1998, nine amino acids (lysine, methionine, glycine, arginine, asparagine, threonine, serine, cysteine and tryptophan) were greater in HOM than in NOM grain. Lysine and methionine content in HOM grain averaged 12 and 13% higher than in NOM grain in both years. The number of amino acids significantly affected by the grain parent was greater than that for maize type each year. A significant maize type × grain parent interaction for a limited number of amino acids suggest that TC Blend grain parents may affect the consistency of amino acid composition in HOM grain. Results of this study demonstrate that the levels of several amino acids, including economically important lysine and methionine, were consistently greater in HOM than in NOM grain across a range of production environments. Modelling with livestock ration balancing software showed that the additional amino acids and oil in HOM added 12–20% to its value as livestock feed.
Proteome analysis of the relationship between bruchid-resistant and -susceptible mungbean genotypes
Authors: Karim Khan Md. Monowar , Khan Ayub , Ishimoto Masao , Kitamura Keisuke , Komatsu Setsuko
Published: March 2006

Mungbean seeds are often attacked by bruchid insects causing serious damage to the grain during storage. The susceptible/resistant characteristics of mungbean against bruchids have been investigated at the protein level. Seeds of the susceptible cultivar Osaka-ryokuto and the resistant near-isogenic line BC20 were collected at 5, 9, 13, 17, 21 and 23 days after flowering. Crude, cytosol and membrane protein fractions were extracted from the seeds for twodimensional polyacrylamide gel electrophoresis analysis. In Osaka-ryokuto six proteins were found in higher amounts compared to BC20 in the crude protein extract. Some of these proteins were homologous to legumin B and liguleless1. And in BC20 one unique protein, homologous to SalF1R, was identified. In the subcellular protein fractions, nine unique proteins were identified in BC20, seven in the cytosol and two in the membrane fractions. These proteins were homologous to chitinase, alanine aminotransferase in membrane, and SalF1R, β-1,3- glucanase, protein phosphatase 2A, peroxidase BP 2A, provicilin and canavalin in the cytosol fractions. Previous findings of many researchers reveal that these are mainly defence-related proteins. Thus, it is suggested that the above proteins may play a role in maintaining the resistance of line BC20.
Relationships among artichoke cultivars and some related wild taxa based on AFLP markers
Authors: Sonnante G. , De Paolis A. , Pignone D.
Published: March 2006

Artichoke,Cynara cardunculusvar.scolymusis a diploid outcrossing species, originated in the Mediterranean basin, which has been much appreciated both for its tasty heads and pharmaceutical properties since ancient times. The species includes two more botanical varieties:C. cardunculusvar.altilis, the cultivated leafy cardoon andC. cardunculusvar.sylvestris, the presumed wild progenitor of artichoke, which are completely interfertile with the cultivated globe artichoke and all together they form the primary gene pool of artichoke. The secondary gene pool includes at least seven wildCynaraspecies. A high level of morphological variation, essentially in head shape and size, is observed in artichoke varieties. Amplified fragment length polymorphism (AFLP) markers were used in order to assess genetic variation and relationships among artichoke varieties and between these and some of their wild relatives. A selected group of wild and cultivated artichoke accessions belonging to different clusters detected on a morphological basis and from various geographical origins was chosen for the analysis. Twenty-four primer combinations were initially tested to evaluate their ability to detect polymorphism between samples. Nine primer combinations were chosen for further analysis on 39 cultivated artichokes, two wild progenitors, one cultivated cardoon, one sample ofC. cornigera, one ofC. humilisand two samples ofC. syriaca. A high level of polymorphism was observed for AFLP markers. The polymorphic bands obtained were scored and used to assess genetic similarity among wild and cultivated accessions and finally to construct a UPGMA dendrogram and principal co-ordinate (PCO) analysis based on Jaccard's similarity index. The artichoke wild progenitor was quite distantly related to the cultigen and occupied a separate branch in the dendrogram. However, wildC. cardunculuswas more similar to the artichoke than were the other wild species, corroborating the idea that it is the wild progenitor of cultivated artichokes. Within the cultivated artichoke, the dendrogram derived from AFLP analysis produced branches which roughly corresponded to the groups obtained on the basis of morphological and physiological characteristics. The groups were homogeneous enough, except for the ‘Romaneschi’ types, which proved to be quite genetically variable, and did not cluster in a single branch. This is interpreted on the grounds of the possible selection pathway of this more modern morpho-group.
Selection for resistance to black pod disease and yield gains prediction by use of selected cocoa varieties in Cameroon
Authors: Nyasse S. , Efombagn Mousseni I. B. , Eskes A. B.
Published: March 2006

Research on resistance to black pod caused by Phytophthora megakarya has been carried out in Cameroon for 40 years. It has yielded a significant database which is currently being exploited for the modelling of disease resistance levels of the major clones selected as candidate parents for the creation of new resistant and consequently more productive cocoa varieties. These outputs are expected to meet the increasing need of producers for improved planting material to extend cultivation into emerging cocoa-growing areas or to renew old cocoa production basins. These outputs have been made possible through an international collaborative effort and, more recently, within the scope of regional or international initiatives sponsored by CFC/ICCO/IPGRI and by CAOBISCO. New selection approaches and methodologies, such as rapid field assessment and early screening tests, have been promoted, along with the use of molecular tools for genome mapping and disease resistance quantitative trait locus (QTL) identification. Promising material has been introduced, evaluated in the laboratory and on-farm, and compared to the local cocoa germplasm. The basic knowledge developed from this local database has enabled the definition of an empirical disease resistance sorting and subsequently a prediction of the yield gains expected from the use of different cocoa clones and possible combinations (progenies) available on-station and in farmers' stands in different agro-ecological growing conditions; or which have to be created following strategies in the new breeding programme.
Desertification and disarray: the threats to plant genetic resources of southern Darfur, western Sudan
Authors: Robinson Jonathan
Published: March 2006

A civil war is being fought in Darfur in western Sudan that has resulted in a humanitarian disaster with large numbers of Sudanese refugees seeking a safe haven in neighbouring Chad. The conflict is largely ecological in origin and is based on competition for natural resources, including plant genetic resources. Western Sudan has relatively low rainfall and supports rainfed sedentary agriculture and nomadic pastoralism, and a range of domesticated plant species is grown under irrigation by seasonal watercourses. Nomadic pastoralist populations move their herds according to established routes of seasonally available range and pasture species. There has always been a delicate balance between the sedentary and nomadic ways of life that through careful use of water and plant genetic resources has maintained the ecology of the region in balance. Drought, deforestation, overpopulation and overgrazing have accelerated desert encroachment and have exerted huge pressures on the ecology of the region. Indigenous plant genetic resources, including many wild species used as famine foods, are the key to livelihoods in the region. The upsurge in violence has resulted in many farmers abandoning their farms and seed stocks. Social systems are disrupted and rehabilitation of agriculture will be very difficult. This article describes domesticated and wild plant genetic resources of southern Darfur and details their importance to livelihoods in the region.
The new use of Sorghum bicolor-derived SSR markers to evaluate genetic diversity in 17 Australian Sorghum species
Authors: Dillon Sally L. , Lawrence Peter K. , Henry Robert J.
Published: March 2006

The Sorghum genus is extremely diverse both morphologically and geographically, however, relatively few of the 25 recognized species have been evaluated genetically. The apparent lack of basic knowledge pertaining to the levels of genetic diversity both within and between the 17 Australian wild species is a major obstacle to both their effective conservation and potential use in breeding programmes. Twelve Sorghum bicolor-derived simple sequence repeat (SSR) markers were evaluated for cross-species amplification in all 25 Sorghum species. The SSR markers were highly polymorphic, with diversity indices ranging from 0.59 to 0.99 with mean of 0.91. Five markers combined were able to differentiate 24 of the 25 Sorghum species, with intra-species polymorphism apparent. Sorghum bicolor-derived SSRs have proven to be an efficient source of markers for genetic diversity studies of the relatively poorly characterized Australian indigenous Sorghum species.
Morpho-agronomic diversity in grasspea (Lathyrus sativusL.)
Authors: Polignano G.B. , Uggenti P. , Alba V. , Bisignano V. , Della Gatta C.
Published: March 2006

In order to describe the phenotypic diversity in a core collection of grasspea, 47 progenies of single plants (pure lines) selected from 25 accessions were evaluated. Sixteen morpho-agronomic characters including seed 3-(β-N-oxalyl)-l-2,3 diaminopropionic acid (β-ODAP) content were studied. Univariate and multivariate analyses (principal component analysis and cluster analysis) were performed to estimate differences between progenies. Some high-yielding lines could be used directly for cultivation as new varieties and/or as parental lines in crossing programmes. Seed β-ODAP concentration varied from 0.24% to 0.64%. However, a medium to high seed β-ODAP level was recorded for most of the lines, and no significant correlation was observed between this and other morphological traits.
Phenotypic diversity in tetraploid wheats collected from Bale and Wello regions of Ethiopia
Authors: Eticha Firdissa , Bekele Endeshaw , Belay Getachew , Börner Andreas
Published: March 2006

The phenotypic diversity of 32 landrace populations of tetraploid wheats originating from the Bale and Wello regions of Ethiopia was studied. Eight heritable qualitative traits (glume hairiness, glume colour, awnedness, awn length, beak awn, awn colour, spike density, seed colour) were measured on 2453 individual plants (45–110 plants per landrace). The frequencies of each phenotypic class were used to estimate and analyse the diversity at different levels (population, altitude, region). Beak awn and seed colour showed the highest diversity index, and glume hairiness the lowest. Glume hairiness, glume colour, beak awn and awn colour were regionally variable, while gradients across altitude were observed for glume hairiness, glume colour and beak awn. Variation was, however, largely due to the differences in the level of the different characters within populations. On a regional basis, a higher mean diversity index was observed for materials from Wello than from Bale. No drastic change in the overall diversity between these collections and those analysed in the 1970s was evident.
Transfer of simple sequence repeat (SSR) markers from major cereal crops to minor grass species for germplasm characterization and evaluation
Authors: Wang M.L. , Barkley N.A. , Yu J.-K. , Dean R.E. , Newman M.L. , Sorrells M.E. , Pederson G.A.
Published: March 2006

A major challenge for the molecular characterization and evaluation of minor grass species germplasm is the lack of sufficient DNA markers. A set of 210 simple sequence repeat (SSR) markers developed from major cereal crops (self-pollinated wheat and rice, mainly self-pollinated sorghum and out-crossing maize) were evaluated for their transferability to minor grass species (finger millet,Eleusine coracana; seashore paspalum,Paspalum vaginatum; and bermudagrass,Cynodon dactylon). In total, 412 cross-species polymorphic amplicons were identified. Over half of the primers generated reproducible cross-species or cross-genus amplicons. The transfer rate of SSR markers was correlated with the phylogenetic relationship (or genetic relatedness) of these species. The average transfer rate of genomic SSR markers was different from the average transfer rate of expressed sequence tag (EST)-SSR markers. The level of polymorphism was significantly higher among species (67%) than within species (34%), and was related to the degree of out-crossing for each species. The level of polymorphism detected within species was 57% from self-incompatible species, 39% from out-crossing species and 20% from self-pollinated species. Genomic SSRs detected a higher level of polymorphism than EST-SSRs. The use of transferred polymorphic SSR markers for the characterization and evaluation of germplasm is discussed.
Biotechnological utilization of plant genetic resources for the production of phytopharmaceuticals
Authors: Rischer H. , Oksman-Caldentey K.-M.
Published: March 2006

Natural products from plants are still important sources for the development of drugs, despite their recent neglect in pharmaceutical discovery programmes. The rapidly dwindling number of species endangers the availability of these natural compounds, which are characterized by the immense chemical and functional diversity ultimately responsible for their pharmaceutical activity. Although many steps in the drug discovery process have been continuously modified during recent years, a common dilemma is still unresolved, i.e. the supply crisis for hits discovered in rare wild plants due to their inaccessibility or lack of reproducibility. New technology, combining tissue culture, functional genomics and metabolomics, shows promise to overcome these problems and even to supply a greater chemical diversity of compounds.
Improvement of medicinal plant quality: aHypericum perforatumliterature review as an example
Authors: Poutaraud A. , Girardin P.
Published: March 2006

Numerous factors influence the chemical quality of medicinal plants from crop establishment to extraction of raw material. The most important ones are described using the example ofHypericum perforatum. Optimization of these factors contributes to the objective of producing a high-quality drug, and a method consisting of three scientific approaches (technological, agronomical, plant breeding) is presented. All data concerning the plant (biology, physiology and environmental impacts) and the active components and by-products (pathway, localization and stability) are useful to adapt and to develop management sequences. Although plant breeding appears to be the principal way of improvement, and gives good results in terms of resistance to pathogens, active component content and yield; the agronomical and the technological approaches are also very important. The technological approach after harvesting is especially important to avoid degradation of the active components and to induce, in some cases, the transformation of by-products to those molecules sought. This integrated method (plant breeding and agronomical and chemical approaches) requires research on different levels of organization from molecule to field, and includes all processing systems from farmers to chemists.
Lichens—a promising source of bioactive secondary metabolites
Authors: Boustie Joël , Grube Martin
Published: March 2006

Lichen-forming fungi are unique organisms, producing biologically active metabolites with a great variety of effects, including antibiotic, antimycobacterial, antiviral, anti-inflammatory, analgesic, antipyretic, antiproliferative and cytotoxic activities. However, only very limited numbers of lichen substances have been screened for their biological activities and their therapeutic potential in medicine. This is certainly due to the difficulties encountered in identification of the species, collection of bulk quantities, and the isolation of pure substances for structure determination and testing activity. Recently, possibilities for bypassing some of these former difficulties have arisen by the introduction of new techniques. This includes axenic cultivation for production of the genuine compounds or new ones, extraction of focused compounds, or synthesis of natural products or their derivatives for testing. Utilizing these new opportunities, the discovery of novel active metabolites, which could serve as lead compounds, is significantly facilitated. At the same time, the evolution of secondary metabolite patterns is studied using phylogenetic approaches. Yet, the genetic background of the complex chemical patterns is poorly understood. The scattered occurrence of some compounds suggests that their production evolved either in parallel or that ancient biosynthetic pathways are abandoned in many lineages. At least, studies on polyketide synthase genes from different lichen groups suggest a high level of gene paralogy. In this context, clades of orthologous polyketide synthase genes, which are often shared with distantly related non-lichenized fungi, can roughly be identified by their sequence similarity and their similar patterns of substitution rates. The functional assignment of paralogs is nevertheless difficult and reasonable only in a few cases. A global approach of the lichen metabolomic features appears to be essential in developing new and viable biotechnological processes which could afford suitable amounts of unique lichen compounds.