bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure and physicochemical properties of defatted and pin‐milled oat bran concentrate fractions separated by air‐classification4
Authors: Stevenson David G. , Eller Fred J. , Jane Jay‐lin , Inglett George E.
Published: May 2008

Oat bran concentrate (OBC) was defatted by supercritical carbon dioxide, pin‐milled and air‐classified into five fractions (<15, 15–18, 18–24, 24–30 and > 30 μm). β‐glucan content (% dry weight) of defatted OBC, its subsequent pin‐milling and the air‐classified fractions in ascending particle size was 14.3, 17.0, 4.3, 5.8, 12.6, 14.7 and 22.4, respectively. High‐performance size‐exclusion chromatography equipped with multi‐angle laser‐light scattering and refractive index detectors showed that amylopectin was the predominant molecule present in all OBC powders but was present in greater concentration in fractions collected that were < 24 μm. Fractions >24 μm, which had the highest β‐glucan contents had higher starch gelatinisation temperatures (measured using differential scanning calorimeter), and had substantially higher peak, breakdown, final and setback paste viscosity (measured using Rapid Visco Analyser, Foss North America, Eden Prairie, MN, USA) compared with the other lower‐β‐glucan containing fractions. No differences in water retention of 25% (w/w) oat powders in water (measured using thermogravimetric analyser) were observed among defatted OBC, its subsequent pin‐milling and the five fractions separated by air‐classification. In particular, differences in pasting properties show that defatted, pin‐milled OBC that is fractionated by air‐classification will have different food applications depending on particle size collected.
Technological effect of red grape antioxidant dietary fibre added to minced fish muscle
Authors: Sánchez‐Alonso Isabel , Borderías Antonio Javier
Published: May 2008

The aim was to study the effect, over 6 months in frozen storage, of addition of grape antioxidant dietary fibre (GADF) to horse mackerel (Trachurus trachurus) minced muscle (MFM) as a technological ingredient. Concentrations of 0, 2 and 4% GADF were added to MFM samples. Protein solubility, water retention, colour, mechanical properties, lipid oxidation and sensory analyses were carried out immediately after preparation of samples and during and after storage at −20° C. Bound water after thawing and cooking minced samples was proportional to the amount of GADF used. Mechanical properties indicated softness and loss of cohesiveness depending on the amount of GADF. There was inhibition of lipid oxidation during frozen storage when GADF was added. Chemical, physical and sensory analyses suggest that GADF is a highly active technological ingredient in frozen dark minced fish.
Production of black rice cake using ground black rice and medium‐grain brown rice
Authors: Lee Jin‐Cheol , Kim Jong‐Dae , Hsieh Fu‐hung , Eun Jong‐Bang
Published: May 2008

Puffed rice cakes were produced from a blend of ground black rice (GBR) and medium‐grain brown rice (GMBR) by using a rice cake machine. Effects of moisture content, heating temperature and heating time on quality of the black rice cake were investigated. The specific volume of black rice cakes showed an increasing trend with increasing tempering moisture, heating temperature and heating time. The hardness of puffed black rice cake decreased as tempering moisture and heating time increased, and was influenced more by GMBR content than heating temperature. In general, the black rice cake lightness and yellowness decreased steadily with increasing GBR content, while tempering moisture, heating temperature and heating time did not significantly affect the colours of black rice cake. On the contrary, the redness increased with increasing GBR contents. The weight loss during tumbling was not found at all puffing conditions.
Detection and quantification of palm mid‐fraction in a chocolate model system
Authors: Moazami Farahany Elham , Selamat Jinap , Che Man Yakoob Bin , Idris Nor Aini
Published: May 2008

The tocopherol and tocotrienol compositions of the genuine cocoa butter (CB) and palm mid‐fraction (PMF) were investigated to introduce a more reliable indicator in detecting PMF in CB. The results suggested that the α‐tocotrienol data presented could be utilised for the detection of the PMF admixture to CB. The PMF was added to CB at different levels. HPLC was used to detect the presence of PMF admixture to CB using α‐tocotrienol as an indicator. The results derived from the model system indicated that increasing the PMF amount at 0–15% to CB resulted in an increase in the concentration of the α‐tocotrienol significantly (P < 0.05). The addition of PMF amount more than 15% did not have any effect on the α‐tocotrienol concentration. A linear plot with a high correlation of 0.9967 was obtained with SE of 1.527. The high correlation obtained indicated good accuracy, reflecting a close relationship between experimental and theoretical predicted value.
Chemical and microbial quality indexes of Norwegian lobsters (Nephrops norvegicus) dusted with sulphites
Authors: Martínez‐Álvarez Óscar , Gómez‐Guillén María del Carmen , Montero Pilar
Published: May 2008

The effect of dusting with a commercial sulphite‐based anti‐melanosis formulation on several chemical quality indexes of Norwegian lobsters (Nephrops norvegicus) was evaluated and compared with a control batch during chilled storage. Dusting with 6% of the commercial product did not exceed the SO2 residual levels permitted by the EU Directive and by the Food and Drug Administration. The additive retarded successfully the occurrence of black spots on the crustacean surface for at least 7 days and also bleached the samples. The prior addition of the sulphite‐based compound did not affect either muscle pH or total volatile basic nitrogen content during storage, although it did produce increased lipid oxidation. The protease activity decreased, and differences in the pool composition of proteases were observed, so serine and cysteine protease activities showing an increase. Finally, the sulphite‐based compound delayed agmatine production and exerted an antimicrobial effect on H2S producers and Enterobacteriaceae.
Occlusal pressure, contact area, force and the correlation with the morphology of the jaw‐closing muscles in patients with skeletal mandibular asymmetry
Authors: GOTO T. K. , YAMADA T. , YOSHIURA K.
Published: May 2008

Summary  The purpose of this study was to investigate the difference in the occlusal force between deviated and non‐deviated sides of the mandible in adult patients with skeletal mandibular asymmetry, and then also compare the findings to those obtained from controls. The absolute and balance data of the occlusal pressure, occlusal contact area and occlusal force of 23 patients and the controls were examined. Correlations between the occlusal force and the morphology of the jaw‐closing muscles were also analysed. The occlusal pressure of patients was not smaller than controls, however, the occlusal contact area and occlusal force in patients were significantly lower than those in the controls. There was no significant difference in the balance of the occlusal contact area and the occlusal force between the right and left sides in the controls, while the balance was shifted to the deviated side in the patients. Interestingly, the balance of the occlusal pressure was very similar between the patients and the controls. Most parameters of the morphology of the jaw‐closing muscles did not show a linear correlation with either the occlusal pressure or force. In conclusion, the occlusal contact area and occlusal force in patients were significantly lower than those in the controls, and also the balance was shifted to the deviated side in patients with skeletal mandibular asymmetry. It is assumed that the morphology and orientation of jaw‐closing muscles may have not linear but complex correlation to the weaker and unbalanced occlusal force in patients.
Regional volumetric change of the tongue during mastication in pigs
Authors: LIU Z. J. , YAMAMURA B. , SHCHERBATYY V. , GREEN J. R.
Published: May 2008

Summary  Structure and movement of the tongue have been studied extensively, but little study has been carried on its 3D deformation and ensuing volumetric changes during various functions. The purpose of this study is to investigate the volumetric changes of a regional section of the tongue during feeding. Four 12‐week‐old Yucatan miniature pigs were used. During natural mastication and water drinking, the width, length, thickness and volumetric changes were measured using six implanted ultrasonic crystals, which circumscribed a wedge‐shaped volume in the region of the tongue body. Jaw movements were videotaped and digitized. Signals from these two sources were synchronized to allow real‐time analyses. Significant volumetric changes (P < 0·001) were found in chewing, ingestion and drinking, and these changes were stereotypical in relation to rhythmic jaw movements. Volumetric change during chewing was not only more regular, but significantly larger (45·6%, P < 0·001) than that during ingestion (31·4%). The volumetric changes were less regular in drinking and the changing range (30·4%) was close to that during ingestion. Real‐time analysis indicated that the volume began increasing at late jaw closing and reached the peak at late power stroke. The increase in duration of volume only took up 33·4% of the total chewing cycle length; significantly shorter than that of volume decrease. Correlation analysis revealed that the change in posterior dorsal and ventral widths had the greatest positive association with volumetric change (r = 0·43) in direction. The covariance calculations further indicated that dimensional changes in length and thickness coupled negatively with volumetric changes in amplitude. These results revealed that regional volumetric change of the tongue occurs during feeding and chewing requires larger volumetric changes than do ingestion and drinking. Volumetric expansion occurs in the phase of power stroke during chewing and is coupled with increases in widths in the direction and with decreases of thickness and length in the amplitude. The results further suggested that the regional volumetric expansion may play the determinant role in functional load production on its surrounding tissues, and may also imply that neuromuscular control of the tongue is region‐specific, a notion incompatible with traditional scheme of categorizing muscle function in the tongue.
Wear of posterior metal‐free polymer crowns after 2 years
Authors: OHLMANN B. , TRAME J.‐P. , DREYHAUPT J. , GABBERT O. , KOOB A. , RAMMELSBERG P.
Published: May 2008

Summary  The objective of this study was to evaluate the clinical wear behaviour of posterior, metal‐free polymer crowns and to compare it with that of metal‐ceramic crowns. After randomization, a total of 120 single crowns were set in posterior teeth. These 120 crowns were divided into three groups: 40 polymer crowns with a glass‐fibre framework (group 1), 40 polymer crowns without framework stabilization (group 2) and 40 metal‐ceramic crowns (control group). Wear was measured by use of gypsum replicas and a 3D laser scanner at baseline and after 2 years. Statistical analysis was performed by use of a mixed‐effects regression model. The mean total wear of posterior single crowns was −19·0 μm (± 18·5 μm) in group 1, −24·3 μm (± 31·5 μm) in group 2 and −7·0 μm (± 8·8 μm) in the control group. Statistical analysis revealed the mean total wear of the polymer crowns in groups 1 (P ≤ 0·01) and 2 (P ≤ 0·01) was significantly greater than in the control group. No significant difference was detected between groups 1 and 2 (P = 0·58). Age, gender and opposing teeth had no significant effect on wear behaviour.
Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamics
Authors: ITOH H. , BABA K. , ARIDOME K. , OKADA D. , TOKUDA A. , NISHIYAMA A. , MIURA H. , IGARASHI Y.
Published: May 2008

Summary  Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought‐wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co‐Cr major connector and heat‐cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three‐dimensional displacements of the RPDs were measured under a simulated 30‐N loading with a displacement transducer type M‐3. Significant effects of “direct retainer design” on bucco‐palatal displacements and “major connector” on mesio‐distal displacements were revealed by 2 × 3 two‐way analysis of variance of abutment teeth movements (P < 0·001 and P = 0·002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of “direct retainer design” on corono‐apical displacements and “major connector” on mesio‐distal displacements (P = 0·001 and P = 0·028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD.
Motor control of jaw muscles in chewing and in isometric biting with graded narrowing of jaw gape
Authors: PRÖSCHEL P. A. , JAMAL T. , MORNEBURG T. R.
Published: May 2008

Summary  When a certain bite force is applied during unilateral chewing, the combination of jaw elevator muscle activities is different than when a comparable force is applied in unilateral isometric biting, e.g. on a force transducer. Masticatory peak force is generated in a nearly isometric phase of the chewing cycle, with a jaw gape of about 1 mm. In contrast, peak force in isometric biting on force measuring equipment usually induces jaw gapes of 6 mm or even more. Therefore, we tested the hypothesis that the jaw gape influences relative activation of elevator muscles in unilateral isometric biting. We further examined whether such influence could explain the different activity combinations of chewing and isometric biting. In thirty asymptomatic males, masseter and temporalis activities were recorded during intermittent isometric biting with jaw gapes of 6, 5, 3, 2 and 1 mm and during unilateral chewing. Activity combinations were described by working/balancing ratios and by temporalis/masseter ratios. With decreasing jaw gape the working/balancing ratio of the posterior temporalis decreased (P < 0·002) while that of the masseter increased (P < 0·001). Likewise, the temporalis/masseter ratio on the balancing side increased (P < 0·001). With decreasing jaw gape, activity ratios of isometric biting approached ratios of chewing. We conclude that: (i) relative jaw muscle activation in isometric biting depends on the jaw gape, (ii) relative muscle activation in chewing resembles relative activation of isometric biting with a small ‘chewing‐like’ gape. This suggests that characteristic activity combinations in chewing are mainly a result of the approximately isometric contraction during the slow closing phase of the chewing cycle.
Prevalence of edentulousness and related factors among elderly Finns
Authors: HAIKOLA B. , OIKARINEN K. , SÖDERHOLM A.‐L. , REMES‐LYLY T. , SIPILÄ K.
Published: May 2008

Summary  Edentulousness is a multifactor phenomenon. While its overall prevalence is diminishing, it is increasing in older age groups. The aim of this study was to assess the prevalence of edentulousness among the elderly in two municipalities in Finland and to estimate different factors related to it. All persons born in the years 1919, 1922, 1925, 1928, 1931, 1934 and 1937 living in two municipalities (Kirkkonummi in the southern part of Finland and Lakeus in the northern part of Finland) were invited to participate in the study in 1997. The target population consisted of 1733 subjects of whom 1191 were disposed to participate in a clinical examination performed by two dentists. Of the subjects, 624 were from the southern district (Kirkkonummi) and 566 were from the northern district (Lakeus). The participation rates were 62% and 78%, respectively. The subjects answered a questionnaire comprising sociodemographical data, questions on dental and general health and health behaviour. Logistic regression analysis was used to assess the associations between edentulousness and potential associating factors. The overall prevalence of edentulousness was 37%; being 53% in the northern region and 22% in the southern region. Edentulousness was positively associated with high age [odds ratio (OR = 1·09), confidence interval (CI = 1·06–1·12)], female gender (OR = 2·06, CI = 1·43–2·94), northern place of residence (OR = 2·01, CI = 1·45–2·78), low level of education (OR = 7·09, CI = 3·18–15·81), cardiovascular diseases (OR = 1·51, CI = 1·03–2·21) and current smoking versus never smoking (OR = 1·73, CI = 1·17–2·55). Social factors were more prominently associated with edentulousness than factors related to general health.
Bruxism and sleep efficiency measured at home with wireless devices
Authors: AHLBERG K. , SAVOLAINEN A. , PAJU S. , HUBLIN C. , PARTINEN M. , KÖNÖNEN M. , AHLBERG J.
Published: May 2008

Summary  The present study comprised 101 (48 men) employees of the Finnish Broadcasting Company with or without irregular shift work, but all with a work week of five shifts in a row followed by 2 days off. The mean age of the subjects was 41·0 years (SD = 9·9). The BiteStrip, a single‐use disposable EMG device was used for one night during the work week to detect sleep bruxism. The Actiwatch Plus actigraph was worn on the non‐dominant wrist for the entire week to evaluate sleep. Total sleep time and fragmentation index, the latter as a measure of sleep efficiency was calculated for the present study. The BiteStrip scores among the participants were: 0– no bruxism: 52·2% (according to the manufacturer, comparable to a sleep laboratory bruxism count of up to 39 over 5 h), 1– mild: 29·3% (40–74 counts), 2– moderate: 12·0%: (75–124 counts) and 3– severe: 6·5% (>125 counts). Severe bruxers slept less during the work week than non‐bruxers (P = 0·009), but severe bruxers slept slightly more than non‐bruxers during days off. The group means of the sleep fragmentation index decreased from start towards the middle of the work week and increased during days off (P = 0·016). The levels of the fragmentation indices were consistently higher in accordance with bruxism severity (P = 0·013). It was concluded that bruxism has a coherent relationship with sleep efficiency and it can be detected at home with a low cost device.
A basic/hydrophobic cleft of the T4 activator MotA interacts with the C‐terminus of E. coli	σ70 to activate middle gene transcription
Authors: Bonocora Richard P. , Caignan Gregori , Woodrell Christopher , Werner Milton H. , Hinton Deborah M.
Published: May 2008

Transcriptional activation often employs a direct interaction between an activator and RNA polymerase. For activation of its middle genes, bacteriophage T4 appropriates Escherichia coli RNA polymerase through the action of two phage‐encoded proteins, MotA and AsiA. Alone, AsiA inhibits transcription from a large class of host promoters by structurally remodelling region 4 of σ70, the primary specificity subunit of E. coli RNA polymerase. MotA interacts both with σ70 region 4 and with a DNA element present in T4 middle promoters. AsiA‐induced remodelling is proposed to make the far C‐terminus of σ70 region 4 accessible for MotA binding. Here, NMR chemical shift analysis indicates that MotA uses a ‘basic/hydrophobic’ cleft to interact with the C‐terminus of AsiA‐remodelled σ70, but MotA does not interact with AsiA itself. Mutations within this cleft, at residues K3, K28 and Q76, both impair the interaction of MotA with σ70 region 4 and MotA‐dependent activation. Furthermore, mutations at these residues greatly decrease phage viability. Most previously described activators that target σ70 directly use acidic residues to engage a basic surface of region 4. Our work supports accumulated evidence indicating that ‘σ appropriation’ by MotA and AsiA uses a fundamentally different mechanism to activate transcription.
In vitro characterization of a carotenoid cleavage dioxygenase from Nostoc sp. PCC 7120 reveals a novel cleavage pattern, cytosolic localization and induction by highlight
Authors: Scherzinger Daniel , Al‐Babili Salim
Published: May 2008

Carotenoid oxygenases catalyse the cleavage of C‐C double bonds forming apocarotenoids, a diverse group of compounds, including retinoids and the precursors of some phytohormones. Some apocarotenoids, like β‐ionone (C13), are ecologically important volatiles released by plants and cyanobacteria. In this work, we elucidated the activity of the Nostoccarotenoid cleavage dioxygenase (NosCCD, previously named NSC1) using synthetic and cyanobacterial substrates. NosCCD converted bicyclic and monocyclic xanthophylls, including myxoxanthophylls, glycosylated carotenoids that are essential for thylakoid and cell wall structure. The products identified revealed two different cleavage patterns. The first is observed with bicyclic xanthophylls and is identical with that of plant orthologues, while the second is novel and occurs upon cleavage of monocyclic substrates at the C9‐C10 and C7′‐C8′ double bonds. These properties enable the enzyme to produce a plenitude of different C10 and C13 apocarotenoids. Expression analyses indicated a role of NosCCD in response to highlight stress. Western blot analyses of Nostoc cells revealed NosCCD as a soluble enzyme in the cytosol, which also accomodates NosCCD substrates. Incubation of the corresponding fraction with synthetic substrates revealed the activity of the native enzyme and confirmed its induction by highlight.
Optical evolution of Nova Ophiuchi 2007 = V2615 Oph
Authors: Munari U. , Henden A. , Valentini M. , Siviero A. , Dallaporta S. , Ochner P. , Tomasoni S.
Published: May 2008

The moderately fast Nova Oph 2007 reached maximum brightness on 2007 March 28 at V= 8.52, B−V=+1.12, V−RC=+0.76, V−IC=+1.59 and RC−IC=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were tV2= 26.5, tB2= 30, tV3= 48.5 and tB3= 56.5 d. The distance to the nova is d= 3.7 ± 0.2 kpc, the height above the Galactic plane is z= 215 pc, the reddening is E(B−V) = 0.90 and the absolute magnitude at maximum is MmaxV=−7.2 and MmaxB=−7.0. The spectrum four days before maximum resembled a F6 supergiant, in an agreement with broad-band colours. It later developed into that of a standard ‘Fe ii’-class nova. Nine days past maximum, the expansion velocity estimated from the width of Hα emission component was ∼730 km s−1, and the displacement from it of the principal and diffuse-enhanced absorption systems was ∼650 and 1380 km s−1, respectively. Dust probably formed and disappeared during the period from 82 to 100 d past maximum, causing (at peak dust concentration) an extinction of ΔB= 1.8 mag and an extra ΔE(B−V) = 0.44 reddening.
Neutralizing IL‐21 and IL‐15 Inhibits Pro‐inflammatory Cytokine Production in Rheumatoid Arthritis
Authors: Andersson A. K. , Feldmann M. , Brennan F. M.
Published: May 2008

Interleukin (IL)‐21 and IL‐15 belong to the common γ‐chain receptor family. IL‐15 represents a novel therapeutic target in rheumatoid arthritis (RA), whereas less is known about the role of IL‐21 in human inflammatory diseases. We have analysed the effects of blocking IL‐21 and IL‐15 on spontaneous production of pro‐inflammatory cytokines in RA synovial cell cultures. RA synovial membrane cells were cultured in the presence of an IL‐21R‐Fc chimera or a neutralizing IL‐15 antibody and production of tumour necrosis factor (TNF)α, IL‐6 and IL‐1β was measured by enzyme‐linked immunosorbent assay (ELISA). Expression of IL‐21 and IL‐15 in RA synovium was measured by RT‐PCR and ELISA. mRNA for IL‐21 and IL‐21R was detected in the culture cell lysates. Protein for IL‐15 was found at detectable levels in the cell lysates. Both the IL‐21R‐Fc chimera and anti‐IL‐15 antibody inhibited cytokine release, although substantially more IL‐21R‐Fc was needed. IL‐21R‐Fc at the highest dose (100 μg/ml) significantly reduced TNFα production by 50%, IL‐6 by 57% and IL‐1β by 81%. Anti‐IL‐15 antibody (5 μg/ml) significantly inhibited TNFα release by 51%, IL‐6 by 37% and IL‐1β by 82% in line with previous published observations. The data confirm that IL‐15 plays a role in RA and suggests that IL‐21 is also involved in driving the pro‐inflammatory cytokine response in RA.
Advances in Type I Diabetes Associated Tolerance Mechanisms
Authors: Chentoufi A. A. , Binder N. R. , Berka N. , Abunadi T. , Polychronakos C.
Published: May 2008

Type 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of insulin‐producing pancreatic β cells by autoreactive T cells. The polygenic trait for T1D risk implicates many genes that have an impact on fundamental immunological processes such as central and peripheral tolerance. Several pieces of evidence have suggested that many of the genetic loci that are directly linked to type 1 diabetes susceptibility modulate the generation and/or the activation of autoreactive T‐lymphocytes. We and others have proposed a critical role for medullary thymic epithelial cells (mTEC) forming the Hassall’s corpuscles in T‐cell tolerance. Indeed, mTEC have been found to express promiscuous self‐antigens, used directly or through thymic dendritic cells to drive either negative selection of insulin‐reacting precursors or their differentiation into naturally occurring regulatory Foxp3+ CD4+ CD25+ T cells. In the periphery, naturally occurring Foxp3+ CD4+ CD25+ regulatory T (Treg) cells represent the master cells in dominant peripheral T‐cell tolerance. The development and function of Treg cells are ultimately linked to IL‐2 and Foxp3 expression. This review addresses recent literature and emerging concepts of central and peripheral T‐cell tolerance with regards to T1D.
Nature’s assembly line: biosynthesis of simple phenylpropanoids and polyketides
Authors: Yu Oliver , Jez Joseph M.
Published: May 2008

Plants produce large amounts of phenylpropanoids, both in terms of molecular diversity and absolute quantity of these compounds. The phenylpropanoids, and the related plant polyketides, have multiple biological functions. They serve to attract pollinators, support secondary cell‐wall growth, provide protection against various plant diseases, and interact with beneficial soil microbes. Their basic chemical properties also make them useful in the biofuel and biomaterial industries. Phenylpropanoid metabolism begins with the amino acid phenylalanine, which feeds into various biosynthetic pathways that generate a wide range of structurally related polyphenolic compounds. This review focuses on four sub‐groups of these polyphenolic compounds – polyketides, stilbenes, isoflavones and catechins. We discuss the biosynthesis of these molecules, their physiological role in plants, and their striking pharmacological and physiological effects on humans. This review also highlights metabolic engineering efforts aimed at increasing or decreasing the amounts of each class of compound in various model plants and crops.
Opium poppy and Madagascar periwinkle: model non‐model systems to investigate alkaloid biosynthesis in plants
Authors: Facchini Peter J. , De Luca Vincenzo
Published: May 2008

Alkaloids represent a large and diverse group of compounds that are related by the occurrence of a nitrogen atom within a heterocyclic backbone. Unlike other types of secondary metabolites, the various structural categories of alkaloids are unrelated in terms of biosynthesis and evolution. Although the biology of each group is unique, common patterns have become apparent. Opium poppy (Papaver somniferum), which produces several benzylisoquinoline alkaloids, and Madagascar periwinkle (Catharanthus roseus), which accumulates an array of monoterpenoid indole alkaloids, have emerged as the premier organisms used to study plant alkaloid metabolism. The status of these species as model systems results from decades of research on the chemistry, enzymology and molecular biology responsible for the biosynthesis of valuable pharmaceutical alkaloids. Opium poppy remains the only commercial source for morphine, codeine and semi‐synthetic analgesics, such as oxycodone, derived from thebaine. Catharanthus roseus is the only source for the anti‐cancer drugs vinblastine and vincristine. Impressive collections of cDNAs encoding biosynthetic enzymes and regulatory proteins involved in the formation of benzylisoquinoline and monoterpenoid indole alkaloids are now available, and the rate of gene discovery has accelerated with the application of genomics. Such tools have allowed the establishment of models that describe the complex cell biology of alkaloid metabolism in these important medicinal plants. A suite of biotechnological resources, including genetic transformation protocols, has allowed the application of metabolic engineering to modify the alkaloid content of these and related species. An overview of recent progress on benzylisoquinoline and monoterpenoid indole alkaloid biosynthesis in opium poppy and C. roseus is presented.
Plant triacylglycerols as feedstocks for the production of biofuels
Authors: Durrett Timothy P. , Benning Christoph , Ohlrogge John
Published: May 2008

Triacylglycerols produced by plants are one of the most energy‐rich and abundant forms of reduced carbon available from nature. Given their chemical similarities, plant oils represent a logical substitute for conventional diesel, a non‐renewable energy source. However, as plant oils are too viscous for use in modern diesel engines, they are converted to fatty acid esters. The resulting fuel is commonly referred to as biodiesel, and offers many advantages over conventional diesel. Chief among these is that biodiesel is derived from renewable sources. In addition, the production and subsequent consumption of biodiesel results in less greenhouse gas emission compared to conventional diesel. However, the widespread adoption of biodiesel faces a number of challenges. The biggest of these is a limited supply of biodiesel feedstocks. Thus, plant oil production needs to be greatly increased for biodiesel to replace a major proportion of the current and future fuel needs of the world. An increased understanding of how plants synthesize fatty acids and triacylglycerols will ultimately allow the development of novel energy crops. For example, knowledge of the regulation of oil synthesis has suggested ways to produce triacylglycerols in abundant non‐seed tissues. Additionally, biodiesel has poor cold‐temperature performance and low oxidative stability. Improving the fuel characteristics of biodiesel can be achieved by altering the fatty acid composition. In this regard, the generation of transgenic soybean lines with high oleic acid content represents one way in which plant biotechnology has already contributed to the improvement of biodiesel.
Biosynthesis of plant pigments: anthocyanins, betalains and carotenoids
Authors: Tanaka Yoshikazu , Sasaki Nobuhiro , Ohmiya Akemi
Published: May 2008

Plant compounds that are perceived by humans to have color are generally referred to as ‘pigments’. Their varied structures and colors have long fascinated chemists and biologists, who have examined their chemical and physical properties, their mode of synthesis, and their physiological and ecological roles. Plant pigments also have a long history of use by humans. The major classes of plant pigments, with the exception of the chlorophylls, are reviewed here. Anthocyanins, a class of flavonoids derived ultimately from phenylalanine, are water‐soluble, synthesized in the cytosol, and localized in vacuoles. They provide a wide range of colors ranging from orange/red to violet/blue. In addition to various modifications to their structures, their specific color also depends on co‐pigments, metal ions and pH. They are widely distributed in the plant kingdom. The lipid‐soluble, yellow‐to‐red carotenoids, a subclass of terpenoids, are also distributed ubiquitously in plants. They are synthesized in chloroplasts and are essential to the integrity of the photosynthetic apparatus. Betalains, also conferring yellow‐to‐red colors, are nitrogen‐containing water‐soluble compounds derived from tyrosine that are found only in a limited number of plant lineages. In contrast to anthocyanins and carotenoids, the biosynthetic pathway of betalains is only partially understood. All three classes of pigments act as visible signals to attract insects, birds and animals for pollination and seed dispersal. They also protect plants from damage caused by UV and visible light.
Prospects for increasing starch and sucrose yields for bioethanol production
Authors: Smith Alison M.
Published: May 2008

In the short term, the production of bioethanol as a liquid transport fuel is almost entirely dependent on starch and sugars from existing food crops. The sustainability of this industry would be enhanced by increases in the yield of starch/sugar per hectare without further inputs into the crops concerned. Efforts to achieve increased yields of starch over the last three decades, in particular via manipulation of the enzyme ADPglucose pyrophosphorylase, have met with limited success. Other approaches have included manipulation of carbon partitioning within storage organs in favour of starch synthesis, and attempts to manipulate source–sink relationships. Some of the most promising results so far have come from manipulations that increase the availability of ATP for starch synthesis. Future options for achieving increased starch contents could include manipulation of starch degradation in organs in which starch turnover is occurring, and introduction of starch synthesis into the cytosol. Sucrose accumulation is much less well understood than starch synthesis, but recent results from research on sugar cane suggest that total sugar content can be greatly increased by conversion of sucrose into a non‐metabolizable isomer. A better understanding of carbohydrate storage and turnover in relation to carbon assimilation and plant growth is required, both for improvement of starch and sugar crops and for attempts to increase biomass production in second‐generation biofuel crops.
Microbial conversion of sugars from plant biomass to lactic acid or ethanol
Authors: Doran‐Peterson Joy , Cook Dana M. , Brandon Sarah K.
Published: May 2008

Concerns for our environment and unease with our dependence on foreign oil have renewed interest in converting plant biomass into fuels and ‘green’ chemicals. The volume of plant matter available makes lignocellulose conversion desirable, although no single isolated organism has been shown to depolymerize lignocellulose and efficiently metabolize the resulting sugars into a specific product. This work reviews selected chemicals and fuels that can be produced from microbial fermentation of plant‐derived cell‐wall sugars and directed engineering for improvement of microbial biocatalysts. Lactic acid and ethanol production are highlighted, with a focus on engineered Escherichia coli.
Platform biochemicals for a biorenewable chemical industry
Authors: Nikolau Basil J. , Perera M. Ann D.N. , Brachova Libuse , Shanks Brent
Published: May 2008

The chemical industry is currently reliant on a historically inexpensive, petroleum‐based carbon feedstock that generates a small collection of platform chemicals from which highly efficient chemical conversions lead to the manufacture of a large variety of chemical products. Recently, a number of factors have coalesced to provide the impetus to explore alternative renewable sources of carbon. Here we discuss the potential impact on the chemical industry of shifting from non‐renewable carbon sources to renewable carbon sources. This change to the manufacture of chemicals from biological carbon sources will provide an opportunity for the biological research community to contribute fundamental knowledge concerning carbon metabolism and its regulation. We discuss whether fundamental biological research into metabolic processes at a holistic level, made possible by completed genome sequences and integrated with detailed structural understanding of biocatalysts, can change the chemical industry from being dependent on fossil‐carbon feedstocks to using biorenewable feedstocks. We illustrate this potential by discussing the prospect of building a platform technology based upon a concept of combinatorial biosynthesis, which would explore the enzymological flexibilities of polyketide biosynthesis.
D’orenone blocks polarized tip growth of root hairs by interfering with the PIN2‐mediated auxin transport network in the root apex
Authors: Schlicht Markus , Šamajová Olga , Schachtschabel Doreen , Mancuso Stefano , Menzel Diedrik , Boland Wilhelm , Baluška František
Published: May 2008

The C18 ketone (5E,7E)‐6‐methyl‐8‐(2,6,6‐trimethylcyclohex‐1‐enyl)octa‐5,7‐dien‐2‐one (D’orenone) has been postulated to be an early cleavage product of β‐carotene en route to trisporic acids; these act as morphogenetic factors during the sexual reproduction of zygomycetes. Here we report that D’orenone blocks the highly polarized tip growth of root hairs, causing tip growth to stop completely within a few minutes. Importantly, external auxin reverses the effects of D’orenone on root hairs. Further analysis revealed that D’orenone lowers the auxin concentration in trichoblasts via PIN2‐mediated auxin efflux to below the critical levels essential for root hair growth. D’orenone specifically increases PIN2 protein abundance without affecting PIN2 transcripts, and the PIN2 expression domain enlarges and shifts basipetally, resulting in more active auxin transport. The observation that D’orenone does not interfere with the root hair growth in roots of null mutant lines provides additional evidence that PIN2 is its specific target.
A novel homodimeric geranyl diphosphate synthase from the orchid Phalaenopsis bellina lacking a DD(X)2–4D motif
Authors: Hsiao Yu‐Yun , Jeng Mei‐Fen , Tsai Wen‐Chieh , Chuang Yu‐Chen , Li Chia‐Ying , Wu Tian‐Shung , Kuoh Chang‐Sheng , Chen Wen‐Huei , Chen Hong‐Hwa
Published: May 2008

Geranyl diphosphate (GDP) is the precursor of monoterpenes, which are the major floral scent compounds in Phalaenopsis bellina. The cDNA of P. bellina GDP synthase (PbGDPS) was cloned, and its sequence corresponds to the second Asp‐rich motif (SARM), but not to any aspartate‐rich (Asp‐rich) motif. The recombinant PbGDPS enzyme exhibits dual prenyltransferase activity, producing both GDP and farnesyl diphosphate (FDP), and a yeast two‐hybrid assay and gel filtration revealed that PbGDPS was able to form a homodimer. Spatial and temporal expression analyses showed that the expression of PbGDPS was flower specific, and that maximal PbGDPS expression was concomitant with maximal emission of monoterpenes on day 5 post‐anthesis. Homology modelling of PbGDPS indicated that the Glu‐rich motif might provide a binding site for Mg2+ and catalyze the formation of prenyl products in a similar way to SARM. Replacement of the key Glu residues with alanine totally abolished enzyme activity, whereas their mutation to Asp resulted in a mutant with two‐thirds of the activity of the wild‐type protein. Phylogenetic analysis indicated that plant GDPS proteins formed four clades: members of both GDPS‐a and GDPS‐b clades contain Asp‐rich motifs, and function as homodimers. In contrast, proteins in the GDPS‐c and GDPS‐d clades do not contain Asp‐rich motifs, but although members of the GDPS‐c clade function as heterodimers, PbGDPS, which is more closely related to the GDPS‐c clade proteins than to GDPS‐a and GDPS‐b proteins, and is currently the sole member of the GDPS‐d clade, functions as a homodimer.
A role for SENSITIVE TO FREEZING2 in protecting chloroplasts against freeze‐induced damage in Arabidopsis
Authors: Fourrier Nicolas , Bédard Jocelyn , Lopez‐Juez Enrique , Barbrook Adrian , Bowyer John , Jarvis Paul , Warren Gareth , Thorlby Glenn
Published: May 2008

The SENSITIVE TO FREEZING2 (SFR2) gene has an important role in freezing tolerance in Arabidopsis thaliana. We show that homologous genes are present, and expressed, in a wide range of terrestrial plants, including species not able to tolerate freezing. Expression constructs derived from the cDNAs of a number of different plant species, including examples not tolerant to freezing, are able to complement the freezing sensitivity of the Arabidopsis sfr2 mutant. In Arabidopsis the SFR2 protein is localized to the chloroplast outer envelope membrane, as revealed by the analysis of transgenic plants expressing SFR2 fusions to GFP, by confocal microscopy, and by the immunological analysis of isolated chloroplasts treated with thermolysin protease. Moreover, the chloroplasts of the sfr2 mutant show clear evidence of rapid damage after a freezing episode, suggesting a role for SFR2 in the protection of the chloroplast.
A simple and rapid technique for detecting protein phosphorylation using one‐dimensional isoelectric focusing gels and immunoblot analysis
Authors: Anderson Jeffrey C. , Peck Scott C.
Published: May 2008

We report a technique for detecting protein phosphorylation that involves isoelectric focusing in a vertical mini‐gel format followed by immunoblot detection of the target protein. This method uses standard protein gel equipment, allows sensitive detection of protein phosphorylation when phosphospecific antibodies are not available, and provides a stoichiometric measure of phosphorylation. We demonstrate the application of this method for observing phosphorylation of an Arabidopsis thaliana protein in response to biotic stress.
Ethylene signaling in Arabidopsis involves feedback regulation via the elaborate control of EBF2 expression by EIN3
Authors: Konishi Mineko , Yanagisawa Shuichi
Published: May 2008

EIN3 is a key transcription factor in the signaling pathway of the plant hormone ethylene in Arabidopsis. Ethylene signaling suppresses the 26S proteasome‐mediated proteolysis of EIN3, the accumulation of which induces ethylene‐responsive gene expression. The proteolysis of EIN3 has been suggested to be mediated by the E3 ubiquitin ligase SCFEBF1/2 that contains either of the two closely related F‐box proteins, EBF1 or EBF2. Here, we demonstrate feedback regulation of ethylene signaling that results from the direct upregulation of the EBF2 gene by EIN3. Although EBF1 and EBF2 show comparable activities as repressors of EIN3‐dependent transcription, our analysis of transgenic Arabidopsis plants has revealed that the EBF2 promoter, but not the EBF1 promoter, is activated by ethylene. Furthermore, the results of protoplast transient assays in vivo and electrophoretic mobility shift assays in vitro have revealed that EIN3 can bind and activate the EBF2 promoter, indicating that EIN3 modulates EBF2 gene expression in planta. An ebf2 mutant transformed with the EBF2 gene under the control of a mutant promoter in which the EIN3‐binding site was disrupted still showed an ethylene hyper‐responsive phenotype, indicating the physiological relevance of EIN3‐mediated activation of the EBF2 gene in the downregulation of ethylene signaling. We show an additional finding that a sequence downstream of the EBF2 coding region is also involved in modulations of both the EBF2 expression level and sensitivity to ethylene. These results thus indicate that the fine‐tuning of ethylene signaling involves the intricate regulation of EBF2 expression in Arabidopsis.
Effect of oregano (O. majorana × O. vulgare) on performance and antioxidative capacity of quails fed a diet rich in ω3 fatty acids
Authors: Handl S. , Hellweg P. , Khol‐Parisini A. , Rossmann B. , Thurner K. , Luf W. , Novak J. , Zentek J.
Published: May 2008

Oregano possesses high antioxidant activity and could therefore be used to enhance oxidative stability of eggs high in ω3 fatty acids. In this study, 20 female quails were fed a diet containing 4% linseed oil. They were divided into two groups, one receiving oregano, and the other grass meal as control (2% respectively). Cholesterol oxidation products were analysed in fresh eggs, in stored eggs and in the livers. Trolox equivalent antioxidative capacity of plasma was measured. No significant differences were seen between the groups.
Prediction of digestible energy value of extruded dog food: comparison of methods
Authors: Hervera M. , Baucells M. D. , Torre C. , Buj A. , Castrillo C.
Published: May 2008

The proposal of National Research Council (NRC), based on the use of modified Atwater factors, is nowadays the widely used method to estimate digestible energy (DE) content of pet foods. Recently, alternative methods have been suggested for predicting energy content of commercial canine dry food. Factorial equations including food fibre content as estimator, in vitro digestions methods or near‐infrared spectroscopy (NIRS) techniques have been considered as good approaches to predict the energy content of dog foods. The aim of this study was to compare the accuracy of some of those estimation methods. Seventeen samples of commercial extruded dog food were used to validate and compare some estimation methods of energy digestibility (Ed, %) and DE value [MJ/kg dry matter (DM)]. The apparent Ed and DE of each food were previously determined by in vivo trials. In vivo Ed and DE of foods ranged from 79.30% to 91.05% and from 16.25 to 21.82 MJ/kg DM, respectively, and their crude fibre (CF) content ranged from 0.72% to 3.28% (in DM base). The % Ed of each sample was estimated by the factorial equation (% Ed = 91.2 − 1.43 × CF %) and by the in vitro digestion method [% Edin vitro = −2.45 + 0.98 organic matter (OM) disappearancein vitro%]. The set of samples also was analysed by NIRS, using a calibration equation developed from a set of 69 samples of commercial extruded dog food (0.76 and 0.89 cross‐validation r2 and 2.33 and 0.61 cross‐validation SE for Ed and DE respectively). The in vitro method gave better estimations of Ed in vivo than NIRS and factorial methods, although all the methods assessed showed a very good and similar accuracy in the prediction of DE value. These three methods showed a slight better accuracy than that previously proposed by the NRC. To consider constant digestibility values of nutrient content of food can result in bias and error in the estimated energy values. The alternative prediction methods used in this study take into account differences of ingredient composition and availability of nutrients of different extruded dog foods thus could be better systems of valuating energy content in a wider range of different kind of foods than in use method.