bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antidiabetic activity of flavone from Ipomoea Batatas leaf in non‐insulin dependent diabetic rats
Authors: Zhao Rui , Li Qingwang , Long Ling , Li Jian , Yang Runjun , Gao Dawei 
Published: October 2006

SummaryThe effects of flavone extracted from Ipomoea batatas leaf (FIBL) on body weight, blood glucose, serum lipid profiles, serum insulin and free radicals in rats with non‐insulin dependent diabetes mellitus (NIDDM) were studied. FIBL treatment (25, 50, 100 mg kg−1) for 2 weeks resulted in a significant decrease in the concentration of plasma triglyceride (TG), plasma cholesterol (TC) and weight in NIDDM rats. Furthermore, FIBL markedly decreased fasting plasma insulin level, blood glucose (FBG) level, low‐density lipoprotein cholesterol (LDL‐C), and malondialdehyde (MDA) levels and significantly increased the Insulin Sensitive Index (ISI) and superoxide dismutase (SOD) level in NIDDM rats. In addition, flavone extracted from I. batatas leaf did not show any physical or behavioural signs of toxicity. More significantly, our data demonstrate the FIBL at the dose of 50 mg kg−1 body weight exhibited the optimal effect. The above results suggest that flavone extracted from I. batatas leaf could control blood glucose and modulate the metabolism of glucose and blood lipid, and decrease outputs of lipid peroxidation and scavenge the free radicals in non‐insulin dependent diabetic rats.
New method to discriminate between cathepsin B and cathepsin L in crude extracts from fish muscle based on a simple acidification procedure
Authors: Godiksen Helene , Nielsen Henrik Hauch 
Published: October 2006

SummaryA new and simple method to distinguish between cathepsin B and cathepsin L in crude extracts of herring (Clupea harengus) muscle has been established. An acid treatment of crude extracts (exposed to pH 3 for 5 min) activated a latent form of cathepsin L and inactivated cathepsin B. Furthermore, in neutral crude extract, the hydrolysis of benzyloxycarbonyl‐l‐phenylalanyl‐l‐arginyl‐4‐methylcoumarine (Z‐Phe‐Arg‐MCA) (cathepsin B and cathepsin L substrates) was between 0% and 15% of the hydrolysis of benzyloxycarbonyl‐l‐arginyl‐l‐arginyl‐7‐amino‐4‐methylcoumarine (Z‐Arg‐Arg‐MCA; cathepsin B substrate). Cathepsin B activity is measured in neutral extract using the specific cathepsin B substrate Z‐Arg‐Arg‐MCA and cathepsin L activity is measured in acid‐treated extract with Z‐Phe‐Arg‐MCA as substrate. The specific cathepsin B inhibitor, CA‐074, did not inhibit the Z‐Arg‐Arg‐MCA significantly without affecting the Z‐Phe‐Arg‐MCA activity. An acid treatment of the crude extract is therefore a more advantageous approach to discriminate between cathepsin B and cathepsin L activities.
RovM, a novel LysR‐type regulator of the virulence activator gene rovA, controls cell invasion, virulence and motility of Yersinia pseudotuberculosis
Authors: Heroven Ann Kathrin , Dersch Petra 
Published: October 2006

SummaryRovA is a MarR‐type transcriptional regulator that controls transcription of rovA, the expression of the primary invasive factor invasin and other virulence genes of Yersinia pseudotuberculosis in response to environmental signals. Using a genetic approach to identify regulatory components that negatively influence rovA expression, we identified a new LysR‐type regulatory protein, designated RovM, which exhibits homology to the virulence regulator PecT/HexA of plant pathogenic Erwinia species. DNA‐binding studies revealed that RovM interacts specifically with a short binding site between promoters P1 and P2 within the rovA regulatory region and negatively modulates rovA transcription in cooperation with the histone‐like protein H‐NS. The rovM gene itself is under positive autoregulatory control and is significantly induced during growth in minimal media as shown in regulation studies. Disruption of the rovM gene leads to a significant increase of RovA and invasin synthesis and enhances internalization of Y. pseudotuberculosis into host cells. Finally, we show that a Y. pseudotuberculosis rovM mutant is more virulent than wild type and higher numbers of the bacteria are detectable in gut‐associated lymphatic tissues and organs in the mouse infection model system. In contrast, elevated levels of the RovM protein, which exert a positive effect on flagellar motility, severely attenuate the ability of Y. pseudotuberculosis to disseminate to deeper tissues. Together, our data show, that RovM is a key regulator implicated in the environmental control of virulence factors, which are crucial for the initiation of a Yersinia infection.
Targeting proteins to the cell wall of sporulating Bacillus anthracis
Authors: Marraffini Luciano A. , Schneewind Olaf 
Published: October 2006

SummaryDormant spores of Bacillus anthracis germinate during host infection and their vegetative growth and dissemination precipitate anthrax disease. Upon host death, bacilli engage a developmental programme to generate infectious spores within carcasses. Hallmark of sporulation in Bacillus spp. is the formation of an asymmetric division septum between mother cell and forespore compartments. We show here that sortase C (SrtC) cleaves the LPNTA sorting signal of BasH and BasI, thereby targeting both polypeptides to the cell wall of sporulating bacilli. Sortase substrates are initially produced in different cell compartments and at different developmental stages but penultimately decorate the envelope of the maturing spore. srtC mutants appear to display no defect during the initial stages of infection and precipitate lethal anthrax disease in guinea pigs at a similar rate as wild‐type B. anthracis strain Ames. Unlike wild‐type bacilli, srtC mutants do not readily form spores in guinea pig tissue or sheep blood unless their vegetative forms are exposed to air.
Tn5 transposase loops DNA in the absence of Tn5 transposon end sequences
Authors: Adams Christian D. , Schnurr Bernhard , Skoko Dunja , Marko John F. , Reznikoff William S. 
Published: October 2006

SummaryTransposases mediate transposition first by binding specific DNA end sequences that define a transposable element and then by organizing protein and DNA into a highly structured and stable nucleoprotein ‘synaptic’ complex. Synaptic complex assembly is a central checkpoint in many transposition mechanisms. The Tn5 synaptic complex contains two Tn5 transposase subunits and two Tn5 transposon end sequences, exhibits extensive protein–end sequence DNA contacts and is the node of a DNA loop. Using single‐molecule and bulk biochemical approaches, we found that Tn5 transposase assembles a stable nucleoprotein complex in the absence of Tn5 transposon end sequences. Surprisingly, this end sequence‐independent complex has structural similarities to the synaptic complex. This complex is the node of a DNA loop; transposase dimerization and DNA specificity mutants affect its assembly; and it likely has the same number of proteins and DNA molecules as the synaptic complex. Furthermore, our results indicate that Tn5 transposase preferentially binds and loops a subset of non‐Tn5 end sequences. Assembly of end sequence‐independent nucleoprotein complexes likely plays a role in the in vivo downregulation of transposition and the cis‐transposition bias of many bacterial transposases.
Genetic variation in Fagus multinervis Nakai (Fagaceae), a beech species endemic to Ullung Island, South Korea
Authors: OHKAWA TOMOSHI , KITAMURA KEIKO , TAKASU HIDEKI , KAWANO SHOICHI 
Published: October 2006

AbstractThe genetic variation of Fagus multinervis Nakai (Fagaceae), which is endemic to Ullung Island, South Korea, was investigated using allozyme polymorphisms as a genetic marker. A total of 1074 individuals collected from five populations were analyzed and the levels of genetic diversity were compared to those of Fagus japonica and Fagus crenata distributed in Japan. The percentages of polymorphic loci and the number of alleles per locus of F. multinervis were similar to those of the other beech species and to other long‐lived woody species. However, the heterozygosities in both direct counts and Hardy–Weinberg’s expected values were considerably higher in F. multinervis and F. japonica, which belong to the same subgenus Engleriana, than the other beech species that belong to another subgenus Fagus. Based on the five allozyme loci, approximately 1.5–3.0‐fold higher mean values of heterozygosities were found in the multistemmed beeches F. multinervis and F. japonica. The reason why such higher rates of heterozygosities were found in these species is also discussed. The proportions of expected effective population sizes (i.e. Nem/Nec, Nej/Nec and Nem/Nej) between the species were calculated, and these were Nem/Nec = 6.57, Nej/Nec = 6.73 and Nem/Nej = 0.98, respectively, in which Nem, Nej and Nec are the effective population sizes of F. multinervis, F. japonica and F. crenata, respectively.
Synchronization between temporal variation in heat generation, floral scents and pollinator arrival in the beetle‐pollinated tropical Araceae Homalomena propinqua
Authors: KUMANO YUKO , YAMAOKA RYOHEI 
Published: October 2006

AbstractInflorescences of beetle‐pollinated plants, such as Araceae, show temporal heat generation, the role of which varies among plants. Homalomena propinqua is a common understory herb in the lowland dipterocarp forests of Borneo. Two species of beetle, Parastasia bimaculata Guerin (Scarabaeidae) and Dercetina sp. (Chrysomelidae), are known to visit inflorescences of this species and subsequently transfer its pollen. In this study, to examine the role of heat generation by inflorescences of H. propinqua, especially as an attractant of pollinators, measurements of the temperature of spadices, behavioral experiments with beetles and chemical analyses of floral scents were carried out. As a result, spadices of H. propinqua exhibited heat generation from 06:30 hours (dawn) until 09:30 hours on both the first and second days of flowering, and this paralleled the arrival of the beetle pollinators. Behavioral tests showed that both beetle pollinators were attracted to spadices significantly more than spathes. Floral scents of H. propinqua were composed of 18 compounds, the main one being 2‐butanol, a highly volatile low molecule compound. The amount of floral scents increased temporally between 07:00 hours and 08:00 hours on the first day of flowering, which was consistent with the arrival of pollinators and heat generation by the spadices. These results indicate that the heat generated by spadices may promote temporal volatilization of floral scents, especially highly volatile compounds such as 2‐butanol, and as a result temporally attracting beetle pollinators.
Varietal effects of eight paired lines of transgenic Bt maize and near‐isogenic non‐Bt maize on soil microbial and nematode community structure
Authors: Griffiths Bryan S. , Heckmann Lars‐Henrik , Caul Sandra , Thompson Jacqueline , Scrimgeour Charlie , Krogh Paul Henning 
Published: October 2006

SummaryA glasshouse experiment was undertaken to provide baseline data on the variation between conventional maize (Zea mays L.) varieties and genetically modified maize plants expressing the insecticidal Bacillus thuringiensis protein (Bt, Cry1Ab). The objective was to determine whether the variation in soil parameters under a range of conventional maize cultivars exceeded the differences between Bt and non‐Bt maize cultivars. Variations in plant growth parameters (shoot and root biomass, percentage carbon, percentage nitrogen), Bt protein concentration in shoots, roots and soil, soil nematode abundance and soil microbial community structure were determined. Eight paired varieties (i.e. varieties genetically modified to express Bt protein and their near‐isogenic control varieties) were investigated, together with a Bt variety for which no near‐isogenic control was available (NX3622, a combined transformant expressing both Bt and herbicide tolerance) and a conventional barley (Hordeum vulgare L.) variety which was included as a positive control. The only plant parameter which showed a difference between Bt varieties and near‐isogenic counterparts was the shoot carbon to nitrogen ratio; this was observed for only two of the eight varieties, and so was not attributable to the Bt trait. There were no detectable differences in the concentration of Bt protein in plant or soil with any of the Bt‐expressing varieties. There were significant differences in the abundance of soil nematodes, but this was not related to the Bt trait. Differences in previously published soil nematode studies under Bt maize were smaller than these varietal effects. Soil microbial community structure, as determined by phospholipid fatty acid (PLFA) analysis, was strongly affected by plant growth stage but not by the Bt trait. The experimental addition of purified Cry1Ab protein to soil confirmed that, at ecologically relevant concentrations, there were no measurable effects on microbial community structure.
Suspension‐cultured BY‐2 tobacco cells produce and mature immunologically active house dust mite allergens
Authors: Lienard David , Dinh Olivia Tran , Van Oort Erika , Van Overtvelt Laurence , Bonneau Caroline , Wambre Eric , Bardor Muriel , Cosette Pascal , Didier‐Laurent Alain , De Borne François Dorlhac , Delon Rene , Van Ree Ronald , Moingeon Philippe , Faye Loïc , Gomord Véronique 
Published: October 2006

SummaryThe replacement of crude allergen extracts by selected allergens currently represents a major goal for the improvement of allergy diagnosis and immunotherapy. Indeed, the development of molecularly defined vaccines would facilitate both standardization and enhance batch‐to‐batch reproducibility as well as treatment specificity. In this study, we have investigated the potential of tobacco plant cells to produce biologically active forms of the two major allergens from the house dust mite. A detailed characterization of these plant‐made allergens has shown similar proteolytic maturation and folding as well as comparable immunoreactivity to their natural counterparts. Altogether, our results exemplify that suspension‐cultured BY‐2 tobacco cells represent a low cost and environmentally safe expression system suitable to produce recombinant allergens from Dermatophagoides pteronyssinus under a form appropriate for diagnostic and therapeutic purposes.
The impact of instructional elements in computer‐based instruction
Authors: Martin Florence , Klein James D. , Sullivan Howard 
Published: October 2006

AbstractThis study investigated the effects of several elements of instruction (objectives, information, practice, examples and review) when they were combined in a systematic manner. College students enrolled in a computer literacy course used one of six different versions of a computer‐based lesson delivered on the web to learn about input, processing, storage and output of a computer. The six versions of the program consisted of (1) a full version that contained information plus objectives, practice with feedback, examples and review, (2) a version without objectives, (3) one without examples, (4) one without practice, (5) one without review and (6) a lean version containing information only. Results indicated participants who used one of the four versions of the computer program that included practice performed significantly better on the posttest and had consistently more positive attitudes than those who did not receive practice. Implications for the development of computer‐based instruction are explored.
Combined longitudinal effects of attitude and subjective norms on student outcomes in a web‐enhanced course: A structural equation modelling approach
Authors: Sivo Stephen A. , Pan Cheng‐Chang ‘Sam’ , Hahs‐Vaughn Debbie L. 
Published: October 2006

AbstractFactors affecting the student use of a course management system in a web‐enhanced course are investigated using the technology acceptance model. Represented in the present study is the second phase of the analysis, with a focus on the causal relationship of subjective norms to student attitudes towards WebCT and their effect on three dependent variables: (1) end‐of‐course grades; (2) online frequency; and (3) future preference to take a web‐enhanced class over a face‐to‐face course. Structural equation modelling was used to analyse the measures of the two independent variables across three time periods. Findings suggest that the proposed model fits the data well and that it is useful to model student attitudes and perceived social pressure to understand certain student outcomes. Further recommendations for researchers and practitioners are addressed.
Educational design as a quest for congruence: The need for alternative learning design tools
Authors: Der‐Thanq Chen , Hung David , Wang Yu‐Mei 
Published: October 2006

AbstractThere is a common predicament faced by educational designers, that is, the lack of learning design tools for nontraditional pedagogies of learning. Because of this lack of alternatives, educational designers often use traditional design tools (such as task analysis) in contexts where nontraditional learning activities (such as collaborative projects) are desired. Because the learning goals of objectivist and alternative epistemologies differ, the designed instructional/learning activities do not match the original goals or desired learning outcomes. It is argued that learning design should be understood of as a quest for congruence between learning epistemologies and designs. This paper proposes an analytical framework to help identify the congruence or lack thereof of a learning design. The framework consists of: (1) the employed epistemology and desired learning outcome, (2) focus of analysis, (3) focus of design and (4) the design process. It is hoped that this framework will provide a lever for developing design tools that are more congruent with alternative pedagogies.
Film: State of Cinema Address: 49th San Francisco International Film Festival, 29 April 2006
Authors: SWINTON TILDA 
Published: October 2006

Letter to a boy from his motherBoy, my darling, You asked me the other day, just as you were dropping off, what people's dreams were like before the cinema was invented. You who talk blabberish and chase rabbits in your sleep, hurrumphing like a dog . . . you who never watch television . . . I've been thinking of your question ever since. I have to talk to some people in America about cinema. I'm going there now on the plane and I can't think of anything but your question...
Technological Upgrading under Tariffs and Equivalent Quotas*
Authors: Chiou Jiunn‐rong , Hwang Hong , Mai Chao‐cheng 
Published: October 2006

AbstractThis paper compares the effect of tariffs and that of equivalent quotas on the domestic firm’s production technology choice when it competes with a foreign firm in the domestic market. It is shown that under Bertrand price competition, the ranking of technology under tariff protection and quota protection is ambiguous, as it depends on the relative strength of the strategic vs output effects. The equivalent quota regime can generate a higher‐technology (implying a lower production cost) choice than the tariff regime if the strategic effect dominates the output effect. In contrast, the technology level is necessarily higher under the tariff regime than under the equivalent quota regime when the firms engage in Cournot quantity competition.
A pediatric twin study of brain morphometry
Authors: Wallace Gregory L. , Eric Schmitt J. , Lenroot Rhoshel , Viding Essi , Ordaz Sarah , Rosenthal Michael A. , Molloy Elizabeth A. , Clasen Liv S. , Kendler Kenneth S. , Neale Michael C. , Giedd Jay N. 
Published: October 2006

Background:  Longitudinal pediatric neuroimaging studies have demonstrated increasing volumes of white matter and regionally‐specific inverted U shaped developmental trajectories of gray matter volumes during childhood and adolescence. Studies of monozygotic and dyzygotic twins during this developmental period allow exploration of genetic and non‐genetic influences on these developmental trajectories.Method:  Magnetic resonance imaging brain scans were acquired on a pediatric sample of 90 monozygotic twin pairs, 38 same‐sex dyzygotic twin pairs, and 158 unrelated typically developing singletons. Structural equation modeling was used to estimate the additive genetic, common environment, and unique environment effects, as well as age by heritability interactions, on measures of brain volumes from these images.Results:  Consistent with previous adult studies, additive genetic effects accounted for a substantial portion of variability in nearly all brain regions with the notable exception of the cerebellum. Significant age by heritability interactions were observed with gray matter volumes showing a reduction in heritability with increasing age, while white matter volume heritability increased with greater age.Conclusion:  Understanding the relative contributions of genetic and nongenetic factors on developmental brain trajectories may have implications for better understanding brain‐based disorders and typical cognitive development.
An fMRI examination of developmental differences in the neural correlates of uncertainty and decision‐making
Authors: Krain Amy L. , Hefton Sara , Pine Daniel S. , Ernst Monique , Xavier Castellanos F. , Klein Rachel G. , Milham Michael P. 
Published: October 2006

Background:  Maturation of prefrontal circuits during adolescence contributes to the development of cognitive processes such as decision‐making. Recent theories suggest that these neural changes also play a role in the shift from generalized anxiety disorder (GAD) to depression that often occurs during this developmental period. Cognitive models of the development of GAD highlight the role of intolerance of uncertainty (IU), which can be characterized behaviorally by impairments in decision‐making. The present study examines potential developmental differences in frontal regions associated with uncertain decision‐making, and tests the impact of IU on these circuits.Methods:  Twelve healthy adults (ages 19–36) and 12 healthy adolescents (ages 13–17) completed a decision‐making task with conditions of varied uncertainty while fMRI scans were acquired. They also completed measures of worry and IU, and a questionnaire about their levels of anxiety and certainty during the task.Results:  Combined group analyses demonstrated significant linear effects of uncertainty on activity within anterior cingulate cortex (ACC). Region of interest (ROI)‐based analysis found a significant interaction of group and IU ratings in ACC. Increased IU was associated with robust linear increases in ACC activity only in adolescents. An ROI analysis of feedback‐related processing found that adolescents demonstrated greater activation during incorrect trials relative to correct trials, while the adults showed no difference in neural activity associated with incorrect and correct feedback.Conclusions:  This decision‐making task was shown to be effective at eliciting uncertainty‐related ACC activity in adults and adolescents. Further, IU impacts ACC activity in adolescents during uncertain decision‐making, providing preliminary support for a developmental model of GAD.