bluuebunny/crossref_metadata_2025 huggingface dataset:
Pip, a Novel Activator of Phenazine Biosynthesis in
Pseudomonas chlororaphis
PCL1391
Authors: Girard Geneviève , Barends Sharief , Rigali Sébastien , van Rij E. Tjeerd , Lugtenberg Ben J. J. , Bloemberg Guido V.
Published: November 2006

Secondary metabolites are important factors for interactions between bacteria and
other organisms.
Pseudomonas chlororaphis
PCL1391 produces the
antifungal secondary metabolite phenazine-1-carboxamide (PCN) that
inhibits growth of
Fusarium oxysporum
f. sp.
radius
lycopersici
the causative agent of tomato foot and root rot. Our
previous work unraveled a cascade of genes regulating the PCN
biosynthesis operon,
phzABCDEFGH
. Via a genetic screen, we
identify in this study a novel TetR/AcrR regulator, named Pip
(
p
henazine
i
nducing
p
rotein), which is
essential for PCN biosynthesis. A combination of a phenotypical
characterization of a
pip
mutant, in
trans
complementation assays of various mutant strains, and electrophoretic
mobility shift assays identified Pip as the fifth DNA-binding protein
so far involved in regulation of PCN biosynthesis. In this regulatory
pathway, Pip is positioned downstream of PsrA (
Pseudomonas
sigma factor regulator) and the stationary-phase sigma factor RpoS,
while it is upstream of the quorum-sensing system PhzI/PhzR. These
findings provide further evidence that the path leading to the
expression of secondary metabolism gene clusters in
Pseudomonas
species is highly
complex.
A Type Ib ParB Protein Involved in Plasmid Partitioning in a Gram-Positive Bacterium
Authors: Yin Ping , Li Tai-Yuan , Xie Mao-Hua , Jiang Lina , Zhang Yi
Published: November 2006

Our current understanding of segregation of prokaryotic plasmids has been derived mainly from the study of the gram-negative bacterial plasmids. We previously reported a replicon of the cryptic plasmid from a gram-positive bacterium,Leifsonia xylisubsp.cynodontis. The replicon contains a putative plasmid partition cassette including a Walker-type ATPase followed by open reading frame 4 without sequence homologue. Here we reported that theorf4gene was essential for maintaining the plasmid stability inL. xylisubsp.cynodontis. Furthermore, the purified orf4 protein specifically and cooperatively bound to direct repeat sequences located upstream of theparAgene in vitro, indicating thatorf4is aparBgene and that the direct repeat DNA sequences constitute a partition site,parS. The location ofparSand the features of ParA and ParB proteins suggest that this plasmid partition cassette belongs to type Ib, representing the first type Ib cassette identified from a gram-positive bacterial plasmid.
Selective Repression of Translation by the Brome Mosaic Virus 1a RNA Replication Protein
Authors: Yi Guanghui , Gopinath K. , Kao C. Cheng
Published: November 2006

Differential expression of viral replication proteins is essential for successful infection. We report here that overexpression of the brome mosaic virus (BMV) 1a protein can repress viral RNA replication in a dosage-dependent manner. Using RNA replication-incompetent reporter constructs, repression of translation from BMV RNA1 and RNA2 was observed, suggesting that the effect on translation of the BMV RNA replication proteins is responsible for the decrease in RNA levels. Furthermore, repression of translation by 1a required the B box in the 5′-untranslated region (5′ UTR); BMV RNA3 that lacks a B box in its 5′ UTR is not subject to 1a-mediated translational inhibition. Mutations in either the methyltransferase or the helicase-like domains of 1a reduced the repression of replication and translation. These results suggest that in addition to its known functions in BMV RNA synthesis, 1a also regulates viral gene expression.
Single-nucleotide polymorphism frequency in a set of selected lines of bread wheat (Triticum aestivum L.)
Authors: Ravel Catherine , Praud Sébastien , Murigneux Alain , Canaguier Aurélie , Sapet Frédéric , Samson Delphine , Balfourier François , Dufour Philippe , Chalhoub Boulos , Brunel Dominique , Beckert Michel , Charmet Gilles
Published: November 2006

Information on single-nucleotide polymorphisms (SNPs) in hexaploid bread wheat is still scarce. The goal of this study was to detect SNPs in wheat and examine their frequency. Twenty-six bread wheat lines from different origins worldwide were used. Specific PCR-products were obtained from 21 genes and directly sequenced. SNPs were discovered from the alignment of these sequences. The overall sequence polymorphism observed in this sample appears to be low; 64 single-base polymorphisms were detected in ~21.5 kb (i.e., 1 SNP every 335 bp). The level of polymorphism is highly variable among the different genes studied. Fifty percent of the genes studied contained no sequence polymorphism, whereas most SNPs detected were located in only 2 genes. As expected, taking into account a synthetic line created with a wild Triticum tauschii parent increases the level of polymorphism (101 SNPs; 1 SNP every 212 bp). The detected SNPs are available at http://urgi.versailles.inra.fr/GnpSNP . Data on linkage disequilibrium (LD) are still preliminary. They showed a significant level of LD in the 2 most polymorphic genes. To conclude, the genome size of hexaploid wheat and its low level of polymorphism complicate SNP discovery in this species.
Physical mapping of the blue-grained gene(s) from Thinopyrum ponticum by GISH and FISH in a set of translocation lines with different seed colors in wheat
Authors: Zheng Qi , Li Bin , Mu Sumei , Zhou Hanping , Li Zhensheng
Published: November 2006

The original blue-grained wheat, Blue 58, was a substitution line derived from hybridization between common wheat (Triticum aestivum L., 2n = 6x = 42, ABD) and tall wheatgrass (Thinopyrum ponticum Liu & Wang = Agropyron elongatum, 2n = 10x = 70, StStEeEbEx), in which one pair of 4D chromosomes was replaced by a pair of alien 4Ag chromosomes (unknown group 4 chromosome from A. ponticum). Blue aleurone might be a useful cytological marker in chromosome engineering and wheat breeding. Cytogenetic analysis showed that blue aleurone was controlled by chromosome 4Ag. GISH analysis proved that the 4Ag was a recombination chromosome; its centromeric and pericentromeric regions were from an E-genome chromosome, but the distal regions of its two arms were from an St-genome chromosome. On its short arm, there was a major pAs1 hybridization band, which was very close to the centromere. GISH and FISH analysis in a set of translocation lines with different seed colors revealed that the gene(s) controlling the blue pigment was located on the long arm of 4Ag. It was physically mapped to the 0.71–0.80 regions (distance measured from the centromere of 4Ag). The blue color is a consequence of dosage of this small chromosome region derived from the St genome. We speculate that the blue-grained gene(s) could activate the anthocyanin biosynthetic pathway of wheat.
Construction and characterization of two BAC libraries fromBrachypodium distachyon, a new model for grass genomics
Authors: Huo Naxin , Gu Yong Q. , Lazo Gerard R. , Vogel John P. , Coleman-Derr Devin , Luo Ming-Cheng , Thilmony Roger , Garvin David F. , Anderson Olin D.
Published: November 2006

Brachypodium is well suited as a model system for temperate grasses because of its compact genome and a range of biological features. In an effort to develop resources for genome research in this emerging model species, we constructed 2 bacterial artificial chromosome (BAC) libraries from an inbred diploid Brachypodium distachyon line, Bd21, using restriction enzymes HindIII and BamHI. A total of 73 728 clones (36 864 per BAC library) were picked and arrayed in 192 384-well plates. The average insert size for the BamHI and HindIII libraries is estimated to be 100 and 105 kb, respectively, and inserts of chloroplast origin account for 4.4% and 2.4%, respectively. The libraries individually represent 9.4- and 9.9-fold haploid genome equivalents with combined 19.3-fold genome coverage, based on a genome size of 355 Mb reported for the diploid Brachypodium, implying a 99.99% probability that any given specific sequence will be present in each library. Hybridization of the libraries with 8 starch biosynthesis genes was used to empirically evaluate this theoretical genome coverage; the frequency at which these genes were present in the library clones gave an estimated coverage of 11.6- and 19.6-fold genome equivalents. To obtain a first view of the sequence composition of the Brachypodium genome, 2185 BAC end sequences (BES) representing 1.3 Mb of random genomic sequence were compared with the NCBI GenBank database and the GIRI repeat database. Using a cutoff expectation value of E  < 10−10, only 3.3% of the BESs showed similarity to repetitive sequences in the existing database, whereas 40.0% had matches to the sequences in the EST database, suggesting that a considerable portion of the Brachypodium genome is likely transcribed. When the BESs were compared with individual EST databases, more matches hit wheat than maize, although their EST collections are of a similar size, further supporting the close relationship between Brachypodium and the Triticeae. Moreover, 122 BESs have significant matches to wheat ESTs mapped to individual chromosome bin positions. These BACs represent colinear regions containing the mapped wheat ESTs and would be useful in identifying additional markers for specific wheat chromosome regions.
Chronic exposure to stretch–shortening contractions results in skeletal muscle adaptation in young rats and maladaptation in old rats
Authors: Cutlip Robert G. , Baker Brent A. , Geronilla Kenneth B. , Mercer Robert R. , Kashon Michael L. , Miller Gerald R. , Murlasits Zsolt , Alway Stephen E.
Published: November 2006

The objective of this research was to investigate skeletal muscle response to a chronic administration of stretch–shortening cycles (SSCs) in young and old rats. Dorsiflexor muscles of old (30 months, n = 5) and young (12 weeks, n = 6) rats were exposed 3 times/week for 4.5 weeks to a protocol of 80 maximal SSCs per exposure in vivo. Skeletal muscle response was characterized by isometric and dynamic performance, as well as by muscle wet mass and quantitative morphological analyses following the exposure period. The performance of the young and old groups was not statistically different at the start of the exposure. By the end of the exposure, however, a statistical difference was noted, as performance increased significantly in the young animals and decreased significantly in the old animals. Muscle wet mass of the left tibialis anterior (TA) in the treated limb was significantly greater in the youngthan in the old animals (p < 0.001), whereas there was no difference in the contra-lateral TA. No degenerative myofibers or changes in non-cellular interstitium were noted in either age group, but a significant increase was observed in the volume of the cellular interstitium in the exposed limb of the old animals (p = 0.01), which is indicative of an inflammatory response. Thus, a chronic exposure of SSCs results in significant performance increase and muscle hypertrophy in young animals, and a significant performance decrease and an increased cellular interstitial response in old animals. These findings suggest that age may impair the ability of skeletal muscle to adapt to repetitive mechanical loading, even in the absence of degeneration.
The photochemistry of ring-substituted cinnamyl acetates
Authors: Fleming S A , Renault L , Grundy E C , Pincock J A
Published: November 2006

The photochemistry of the (E)-cinnamyl acetates ((E)-1-aryl-3-propenyl acetates, 8a–8e) with substituents H, 4-CH3O, 3-CH3O, 4-CF3, and 3-CF3, respectively, was examined in both cyclohexane and methanol solvents. Alkene isomerization (E to Z) occurred more efficiently than other reactions and evidence is presented that this process occurs from the excited triplet state. In a slower process, 1,3-migration of the acetoxy group led to the rearranged 3-aryl-3-propenyl acetate isomers (9a–9e) as the major pathway, particularly in cylohexane. In methanol, the isomeric ethers 3-aryl-3-methoxypropene (14) and 1-aryl-3-methoxypropene (15) were formed by reaction of methanol with the photochemically generated cation. The combined yield of 14 and 15 (95% and 5%, respectively) was quantitative for the 4-methoxyphenyl compound (8b). Independent irradiations of the isomers 9a–9c demonstrated that the ethers 14 and 15 were primary photoproducts from 8 and not secondary photoproducts from 9. Fluorescence quantum yields and excited singlet state lifetimes indicated that the reactions, other than the E to Z isomerization, are from the excited singlet state.Key words: cinnamyl acetates, photochemistry, E/Z isomerization, photocleavage, fluorescence.
CIC Medal Award Lecture — Molecular keystones: Lessons from bioorganic reaction mechanisms
Authors: Kluger Ronald
Published: November 2006

The work of the author is reviewed in terms of "keystone molecules" that serve as figurative points of support to understand the interactions of smaller molecules within biological macromolecules. The review emphasizes lessons learned in carboxylation of biotin, reactions of cyclic phosphates, the uses of acyl phosphate monoesters, and the mechanism of decarboxylation of thiamin-derived intermediates.Key words: CIC medal, biotin, ATP, mechanisms, cyclic phosphates, thiamin, acyl phosphates, catalysis.
Characterization of the glyoxalase I gene from the vascular wilt fungus Verticillium dahliae
Authors: Klimes A , Neumann M J , Grant S J , Dobinson K F
Published: November 2006

A glyoxalase I gene homologue (VdGLO1) was identified in the vascular wilt fungus Verticillium dahliae by sequence tag analysis of genes expressed during resting structure development. The results of the current study show that the gene encodes a putative 345 amino acid protein with high similarity to glyoxalase I, which produces S-D-lactoylglutathione from the toxic metabolic by-product methylglyoxal (MG). Disruption of the V. dahliae gene by Agrobacterium tumefaciens-mediated transformation resulted in enhanced sensitivity to MG. Mycelial growth of disruption mutants was severely reduced in the presence of 5 mmol/L MG. In contrast, spore production in liquid medium was abolished at 1 mmol/L MG, although not at physiologically relevant concentrations of ≤100 µmol/L. In this first report on the characterization of a glyoxalase I gene in a vascular wilt pathogen, we found that disruption of VdGLO1 had no discernable effect on the pathogenicity of V. dahliae. These data suggest that while the glyoxalase system is necessary for effectively dealing with catastrophic levels of MG, under normal conditions of growth and infection, other MG detoxification pathways in V. dahliae are able to compensate for the absence of the glyoxalase system.Key words: verticillium wilt, glycolytic methylglyoxal pathway, 2-oxoaldehydes.
Effects of external phosphate concentration on glucose-6-phosphate dehydrogenase gene expression in the arbuscular mycorrhizal fungus Glomus intraradices
Authors: Stewart L I , Jabaji-Hare S , Driscoll B T
Published: November 2006

Specific primers were developed to amplify a 227 bp segment of the arbuscular mycorrhizal fungus Glomus intraradices gene encoding glucose-6-phosphate dehydrogenase (G6PDH), an enzyme involved in the pentose phosphate pathway. G6PDH gene expression was measured by real-time quantitative reverse transcriptase – polymerase chain reaction in response to phosphorus (P) concentrations in the growth medium of colonized transformed carrot roots. We investigated the effects of different P concentration treatments on carbon (C) metabolism within the intraradical mycelia of G. intraradices. The results showed a significant (P = 0.017) down-regulation of G6PDH expression in the intraradical mycelia of G. intraradices cultures grown in high P than low P conditions but no significant difference in regulation in excessive P concentrations when compared with the low P or high P concentrations. These results indicate that a reduction in the C flow from the host could be occurring as a result of elevated P and that a decrease in fungal G6PDH gene expression occurs, but not in the short term (less than 2 h). Reduced C flow from the host could lead to reduced fungal growth and root colonization, as was observed under high soil P conditions.Key words: arbuscular mycorrhizal fungi, phosphorus, nutrient uptake, glucose-6-phosphate dehydrogenase, gene expression.
Exploration of members ofAspergillussectionsNigri,Flavi, andTerreifor feruloyl esterase production
Authors: Bouzid Ourdia , Record Eric , Asther Michèle , Haon Mireille , Navarro David , Asther Marcel , Lesage-Meessen Laurence
Published: November 2006

The ability of members of Aspergillus sections Nigri, Flavi, and Terrei to produce feruloyl esterases was studied according to their substrate specificity against synthetic methyl esters of hydroxycinnamic acids. Type A feruloyl esterases (FAEA), induced during growth on cereal-derived products, show a preference for the phenolic moiety of substrates that contain methoxy substitutions, as found in methyl sinapinate, whereas type B feruloyl esterases (FAEB) show a preference for the phenolic moiety of substrates that contain hydroxyl substitutions, as occurs in methyl caffeate. All the strains of Aspergillus section Nigri (e.g., A. niger and A. foetidus) were able to produce feruloyl esterases with activity profiles similar to those reported for FAEA and FAEB of A. niger when grown on oat–spelt xylan and sugar beet pulp, respectively. The two genes encoding these proteins, faeA and faeB, were identified by Southern blot analysis. The strains of Aspergillus sections Flavi (e.g., A. flavus, A. flavo-furcatus, and A. tamarii) and Terrei (e.g., A. terreus) were able to produce type A and type B enzymes. faeA was revealed in genomic DNA of these strains, and FAEA was determined by immunodetection in cultures grown in oat–spelt xylan. In addition, type B enzymes, not related to faeB, were efficiently induced by oat–spelt xylan and exhibited very original activity profiles on sugar beet pulp. This work confirms that the members of the genus Aspergillus are good feruloyl esterase producers.Key words: Aspergillus, Nigri, Flavi, Terrei, feruloyl esterase.
Variations in parametrial white adipose tissue mass during the mouse estrous cycle: relationship with the expression of peroxisome proliferator-activated receptor-γ and retinoic acid receptor-α
Authors: Gui Yaoting , Cai Zhiming , Silha Josef V. , Murphy Liam J.
Published: November 2006

Estrogen and progestin participate in the regulation of adipose tissue metabolism, and peroxisome proliferator-activated receptor-gamma (PPARγ) and retinoic acid receptor-alpha (RXRα) are absolutely required for adipose tissue development. The present study is to investigate the changes in parametrial fat mass and expression of PPARγ and RXRα during estrous cycle in mice. Parametrial white adipose tissues (WAT), inter-scapula brown adipose tissues, and uteri from female mice were weighed. Blood samples were collected for the measurement of 17 β-estradiol and progesterone levels. An RNase protection assay and Western blot analysis were used to compare the expression of PPARγ and RXRα in adipose tissue. The mass of parametrial WAT in diestrus was significantly higher compared with estrus. However, there is no significant difference on the mass of brown adipose tissues during estrous cycle. The expression of PPARγ in WAT in diestrus was significantly higher than that in estrus. The expression of RXRα during estrous cycle was unchanged in both white and brown adipose tissues. In conclusion, the variation in parametrial WAT mass during the mouse estrous cycle correlates with changes in the expression of PPARγ in WAT.
Habitat requirements of the Yellow-bellied Sapsucker,Sphyrapicus varius, in boreal mixedwood forests of northwestern Canada
Authors: Savignac C. , Machtans C.S.
Published: November 2006

Despite its role as a keystone species, few studies have investigated the habitat requirements of the Yellow-bellied Sapsucker ( Sphyrapicus varius (L., 1766)) in the northwestern part of its range, where the current forest harvesting rotation schedule and targets for reducing the prevalence of old and mixedwood stands may reduce the optimal habitat for this species. We studied nesting and foraging habitat requirements of nesting sapsuckers in a boreal mixedwood forest of northwestern Canada by collecting data on nesting sites and foraging substrates on twenty-four 16- to 56-ha plots distributed among four habitat types in 1998 and 2002. Nests (n = 68) were generally found in large (≥22 cm diameter at breast height) trembling aspen ( Populus tremuloides Michx) that were alive but declining and that showed high incidence (81.1%) of heartwood rot infection ( Phellinus tremulae (Bondarzev) Bondarzev & Borisov in Bondarzev). Nest-site use by sapsuckers was predicted mainly by the presence of external fungal conks and tree diameter. Among tree species used as foraging substrates, paper birch ( Betula papyrifera Marsh.) (65.6%) and green alder ( Alnus viridis (Vill.) Lam. & DC.) (21.3%) were used most frequently. The use of birch was strongly correlated with its availability. Mature forests had higher densities of nesting sites and foraging substrates than immature aspen stands. In addition to reconfirming the importance of mature mixedwood forests for Yellow-bellied Sapsuckers, our study also indicates that forest harvest rotations in northwestern Canada should exceed 90 years to promote the keystone role of this species.
Seasonal and annual movement patterns of polar bears on the sea ice of Hudson Bay
Authors: Parks E.K. , Derocher A.E. , Lunn N.J.
Published: November 2006

Polar bears ( Ursus maritimus Phipps, 1774) move thousands of kilometres over sea ice searching for mates and hunting for seals, which are their primary prey. Recently, decreased sea ice extent and earlier ice break-up have been linked to shifts in seal distribution and abundance and to declines in polar bear condition and numbers in the western Hudson Bay polar bear population. We used geographic positioning system and satellite collars deployed between 1991 and 2004 to quantify movement patterns of adult female polar bears on the sea ice of Hudson Bay in relation to reproductive class and temporal variations in sea ice patterns. We tested whether reproductive status and season affected movement and whether temporal changes in movement were correlated with temporal changes in sea ice patterns in Hudson Bay. Movement patterns were not dependent on reproductive status but did change significantly with season. Annual distances moved and areas covered by bears in Hudson Bay have decreased since 1991, which suggests that measured declines in bear condition and numbers are due to reduced prey intake as opposed to increased energy output. These declines in bear movement are correlated with progressively earlier ice break-up in western Hudson Bay.
Female mating frequency increases with temperature in two cricket species, Gryllodes sigillatus and Acheta domesticus (Orthoptera: Gryllidae)
Authors: Kindle Tashika K. , Johnson Kristen M. , Ivy Tracie M. , Weddle Carie B. , Sakaluk Scott K.
Published: November 2006

Although the effect of temperature on calling song of male crickets has been widely studied, its influence on female mating behaviour remains largely unexplored. We examined the effect of varying temperature on female mating frequency in two cricket species ( Gryllodes sigillatus (F. Walker, 1869) (= Gryllodes supplicans (F. Walker, 1859)) and Acheta domesticus L., 1758) by providing females with multiple mating partners and recording the number of matings over 72 h intervals using time-lapse video recording. Female mating frequency increased with temperature in both species, but increased more steeply in A. domesticus than in G. sigillatus. Temperature accounted for approximately 50% of the variation in female mating frequency. These results suggest that the threshold for mating in females is temperature dependent, such that at lower temperatures only certain males are able to elicit the female mounting response required for successful mating. If temperature affects female selectivity, then male mating success in different seasons may vary, with a wider range of males gaining the opportunity to copulate at warmer times of the year. Consequently, the intensity of sexual selection may vary seasonally.
MICROSCOPIC QUANTUM MECHANICAL FOUNDATION OF FOURIER'S LAW
Authors: MICHEL MATHIAS , GEMMER JOCHEN , MAHLER GÜNTER
Published: November 2006

Besides the growing interest in old concepts such as temperature and entropy at the nanoscale, theories of relaxation and transport have recently regained a lot of attention. With the electronic circuits and computer chips getting smaller and smaller, a fresh look on the equilibrium and nonequilibrium thermodynamics at small length scales far below the thermodynamic limit, i.e. on the theoretical understanding of original macroscopic processes, e.g. transport of energy, heat, charge, mass, magnetization, etc., should be appropriate. Only from the foundations of a theory its limits of applicability may be inferred. This review tries to give an overview on the background and recent developments in the field of nonequilibrium quantum thermodynamics, focusing on the transport of heat in small quantum systems.
Case study analysis and the remediation of misconceptions about respiratory physiology
Authors: Cliff William H.
Published: November 2006

Most students enter the physiology classroom with one or more fundamental misconceptions about respiratory physiology. This study examined the prevalence of four respiratory misconceptions and determined the role of case analysis in the remediation of one of them. A case study was used to help students learn about oxygen transport in the blood and a conceptual diagnostic test was used to assess student understanding of the relation between Po2 and hemoglobin saturation by probing for the corresponding (Sa/Po2) misconception. A 36% remediation of the Sa/Po2 misconception was found to be associated with case analysis. This repair was selective since the frequency of three other respiratory misconceptions was found to be unchanged after classroom instruction about respiratory physiology in lectures and laboratories. Remediation of the Sa/Po2 misconception before an instructor-led, in-class case review was superficial and temporary. Explanations provided by students who correctly answered the Sa/Po2 conceptual diagnostic test showed improved conceptual understanding following case analysis. These results suggest that a learning strategy where students actively confront their faulty notions about respiratory physiology is useful in helping them overcome their misconceptions.
Anthropometric evaluations of body composition of undergraduate students at the University of La Réunion
Authors: Tarnus Evelyne , Bourdon Emmanuel
Published: November 2006

A positive correlation is well established between obesity and the susceptibility to develop metabolic syndrome, a multifactorial disease dramatically associated with an enhanced mortality risk in the developed world. A high prevalence of obesity has recently been described at La Réunion Island, a French department in the Indian Ocean. Anthropometry is generally considered as the single most easily obtainable, inexpensive, and noninvasive method that reflects body composition. At the University of La Réunion, a laboratory course involving students was designed to teach anthropometric measurements for the determination of body composition. Using skin fold thickness equations, students determined the fat and total muscular masses of their body composition. The influences of sex and their physical activity or inactivity on these different parameters were compared and interpreted at the end of the course. Positive and significant correlations were established between the students' body mass indexes values and their fat mass percentages and between their fat-free and muscular masses as well. A higher fat mass percentage was found in sedentary students compared with more active ones. Therefore, this laboratory makes the students practice and understand the use of classical techniques to evaluate the body composition of a person. It also alerts them to the correlation between a sedentary attitude and higher body fat content. This laboratory course constitutes an active introduction to a following lesson on more recent and actual techniques used to evaluate body composition.
Differential response of type 2 deiodinase gene expression to photoperiod between photoperiodic Fischer 344 and nonphotoperiodic Wistar rats
Authors: Yasuo Shinobu , Watanabe Miwa , Iigo Masayuki , Nakamura Takahiro J. , Watanabe Tsuyoshi , Takagi Tsuyoshi , Ono Hiroko , Ebihara Shizufumi , Yoshimura Takashi
Published: November 2006

The molecular basis of seasonal or nonseasonal breeding remains unknown. Although laboratory rats are generally regarded as photoperiod-insensitive species, the testicular weight of the Fischer 344 (F344) strain responds to photoperiod. Recently, it was clarified that photoperiodic regulation of type 2 iodothyronine deiodinase ( Dio2) in the mediobasal hypothalamus (MBH) is critical in photoperiodic gonadal regulation. Strain-dependent differences in photoperiod sensitivity may now provide the opportunity to address the regulatory mechanism of seasonality by studying Dio2 expression. Therefore, in the present study, we examined the effect of photoperiod on Dio2 expression in photoperiod-sensitive F344 and photoperiod-insensitive Wistar rats. A statistically significant difference was observed between short and long days in terms of testicular weight and Dio2 expression in the F344 strain, while no difference was observed in the Wistar strain. These results suggest that differential responses of the Dio2 gene to photoperiod may determine the strain-dependent differences in photoperiod sensitivity in laboratory rats.
Angiotensin-converting enzyme inhibition aggravates renal interstitial injury resulting from partial unilateral ureteral obstruction in the neonatal rat
Authors: Chen Christina O. , Park Matthew H. , Forbes Michael S. , Thornhill Barbara A. , Kiley Susan C. , Yoo Kee Hwan , Chevalier Robert L.
Published: November 2006

Congenital urinary tract obstruction is the most important cause of renal insufficiency in infants and children, and angiotensin-converting enzyme (ACE) inhibitors attenuate the progression of renal disease in adults. ACE inhibitors are increasingly utilized in children with progressive renal disease. Because angiotensin is necessary for normal renal development, we examined the effects of ACE inhibition both during and immediately following the period of postnatal nephrogenesis in the neonatal rat subjected to sham operation or partial unilateral ureteral obstruction (UUO) under general anesthesia within the first 48 h of life. Rats in group I received enalapril 30 mg/kg body wt (or vehicle) daily for the first 10 days, while in group II, the 10 days of treatment began 10 days after surgery. Kidneys were harvested at day 21 and analyzed for apoptosis (TUNEL), interstitial macrophages (ED-1 immunohistochemistry), myofibroblasts (α-smooth muscle actin), and collagen (Sirius red). Partial UUO delayed glomerular maturation and increased ipsilateral renal macrophage infiltration, α-smooth muscle actin and Sirius red staining. In group I, enalapril increased myofibroblast accumulation in sham-operated kidneys, but not in obstructed kidneys. In contrast, in group II, enalapril further increased macrophage, myofibroblast, and collagen accumulation following partial UUO. The relative abundance of components of the kallikrein-kinin system, measured by Western blot, was not altered by partial UUO in the 14- and 28-day-old rat. Thus, in contrast to its salutary effects at later ages, ACE inhibition can worsen injury to the partially obstructed kidney during renal maturation even after the completion of nephrogenesis.
Identification of Basolateral Amygdala Projection Cells and Interneurons Using Extracellular Recordings
Authors: Likhtik Ekaterina , Pelletier Joe Guillaume , Popescu Andrei T. , Paré Denis
Published: November 2006

This study tested whether firing rate and spike shape could be used to distinguish projection cells from interneurons in extracellular recordings of basolateral amygdala (BLA) neurons. To this end, we recorded BLA neurons in isoflurane-anesthetized animals with tungsten microelectrodes. Projection cells were identified by antidromic activation from cortical projection sites of the BLA. Although most projection cells fired spontaneously at low rates (<1 Hz), an important subset fired at higher rates (up to 6.8 Hz). In fact, the distribution of firing rates in projection cells and unidentified BLA neurons overlapped extensively, even though the latter cell group presumably contains a higher proportion of interneurons. The only difference between the two distributions was a small subset (5.1%) of unidentified neurons with unusually high firing rates (9–16 Hz). Similarly, distributions of spike durations in both cell groups were indistinguishable, although most of the fast-firing neurons had spike durations at the low end of the distribution. However, we observed that spike durations depended on the exact position of the electrode with respect to the recorded cell, varying by as much as 0.7 ms. Thus neither firing rate nor spike waveform allowed for unequivocal separation of projection cells from interneurons. Nevertheless, we propose the use of two firing rate cutoffs to obtain relatively pure samples of projection cells and interneurons: ≤1 Hz for projection cells and ≥7 Hz for fast-spiking interneurons. Supplemented with spike-duration cutoffs of ≥0.7 ms for projection cells and ≤0.5 ms for interneurons, this approach should keep instances of misclassifications to a minimum.
A new composite implicit iterative process for a finite family of nonexpansive mappings in Banach spaces
Authors: Gu Feng , Lu Jing
Published: November 2006

The purpose of this paper is to study the weak and strong convergence of implicit iteration process with errors to a common fixed point for a finite family of nonexpansive mappings in Banach spaces. The results presented in this paper extend and improve the corresponding results of Chang and Cho (2003), Xu and Ori (2001), and Zhou and Chang (2002).
Surface Functionalization of Multiwalled Carbon Nanotube with Trifluorophenyl
Authors: Dang Zhi-Min , Wang Lan , Zhang Li-Pei
Published: November 2006

A new approach to dispersion of multiwalled carbon nanotube (MWNT)
in common polar solvents was reported. Here, a detailed study of
nanotube chemistry by using trifluorophenyl (TFP) to modify the
surface of MWNT was discussed, which was not reported before. A
characterization of the reaction products using a variety of
techniques was provided. The results confirmed that the surface of
MWNT was successfully functionalized. Furthermore, trifluorophenyl
multiwalled carbon nanotube (TFP‐MWNT) was well dispersed in polar
solvents, such as tetrahydrofuran (THF), acetic acid (Ac),
N,N‐dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), due to
the adsorption of trifluorophenyl groups on the surface of raw
MWNT. Following chemical modification, dispersed individual
nanotube suggests the potentials for wide applications.
Effects of Ginkgo biloba Extract on Inflammatory Mediators (SOD, MDA, TNF‐α, NF‐κBp65, IL‐6) in TNBS‐Induced Colitis in Rats
Authors: Zhou Yan-Hong , Yu Jie-Ping , Liu Yi-Fei , Teng Xiao-Jun , Ming Mei , Lv Peng , An Ping , Liu Shi-Quan , Yu Hong-Gang
Published: November 2006

Inflammatory mediators play a criticial role in ulcerative colitis immune and inflammatory processes. The aim of the study was to investigate the effects of Ginkgo biloba extract on inflammatory mediators (SOD, MDA, TNF‐α, NF‐κBp65, IL‐6) in TNBS‐induced colitis in rats. Colitis in rats was induced by colonic administration with 2,4,6‐trinitrobenzene sulfonic acid (TNBS, 150 mg/kg). EGB in doses of (50, 100, 200 mg/kg) was administered for 4 weeks to protect colitis. The results showed that EGB could significantly ameliorate macroscopic and histological damage, evidently elevate the activities of SOD and reduce the contents of MDA, inhibit the protein and mRNA expressions of TNF‐α, NF‐κBp65, and IL‐6 in the colon tissues of experimental colitis in a dose‐dependent manner compared with the model group. We concluded that the probable mechanisms of EGB ameliorated inflammatory injury in TNBS‐induced colitis in rats by its modulation of inflammatory mediators and antioxidation.
A Phase II Study of Flavopiridol in Patients With Previously Untreated Advanced Soft Tissue Sarcoma
Authors: Morris Don G. , Bramwell Vivien H. C. , Turcotte Robert , Figueredo Alvaro T. , Blackstein Martin E. , Verma Shail , Matthews Sarah , Eisenhauer Elizabeth A.
Published: November 2006

Purpose. Flavopiridol is a potent cyclin‐dependent kinase (CDK) inhibitor that has preclinical activity in many tumours. This synthetic flavonoid was tested in a phase II nonrandomized, nonblinded multicentre clinical trial to determine its activity and toxicity in patients with previously untreated metastatic or locally advanced soft tissue sarcoma. Methods. A total of 18 patients with histologically confirmed nonoperable soft tissue was treated with flavopiridol administered at a dose of 50 mg/m2 IV over 1 hour daily ×3 days every 3 weeks. Results. Eighteen patients were accrued to the study over a period of 6 months. No objective responses were noted in the seventeen evaluable patients. Eight patients (47%) exhibited stable disease after 2 cycles (median duration of 4.3 months (range 1.4–6.9 months). Kaplan‐Meier estimates for 3‐ and 6‐month progression‐free survivial rates were 44 percent and 22 percent, respectively. The only grade 3 toxicities were diarrhea (N = 2), nausea (N = 2), gastritis (N = 1), and fatigue (N = 1). Ninety‐four percent of patients received ≥ 90% of the planned dose intensity, during 55 treatment cycles. Conclusions. Flavopiridol was well tolerated at the dose and schedule used in this study, however, no objective treatment responses were seen and thus our results do not support further exploration of flavopiridol as a monotherapy at this dose and schedule in soft tissue sarcomas.
Imaging Mitogen-Activated Protein Kinase Function in Xenograft Models of Prostate Cancer
Authors: Ilagan Romyla , Pottratz Jill , Le Kim , Zhang Liqun , Wong Steven G. , Ayala Raul , Iyer Meera , Wu Lily , Gambhir Sanjiv S. , Carey Michael
Published: November 2006

Mitogen-activated protein kinases (MAPK) play important roles in malignancy. The ability to detect and quantitate MAPKs in live animal models of cancer will facilitate an understanding of disease progression. We have developed a gene expression-based imaging system that detects and quantifies MAPK activity in prostate cancer tumors implanted into severe combined immunodeficient mice. The imaging technology uses a modified version of two-step transcriptional amplification (TSTA). The tissue specificity of gene expression is imparted by an enhanced version of the prostate-specific antigen regulatory region that expresses GAL4-ELK1. GAL4-ELK1 confers MAPK specificity by activating a firefly luciferase (FLuc) reporter gene when the Ets-like transcription factor (ELK) 1 activation domain is phosphorylated by MAPK. FLuc activity in live animals was detected using the Xenogen In vivo Imaging System. We validated the TSTA-ELK1 system by analyzing its response to epidermal growth factor treatment in transfected tissue culture cells and in adenovirus (AdTSTA-ELK1)–injected prostate cancer xenograft tumors. We measured MAPK activity in two well-characterized xenograft models, CWR22 and LAPC9. Although no significant differences in MAPK levels were detected between androgen-dependent and androgen-independent xenografts, the CWR22 models display significantly higher levels of AdTSTA-ELK1 activity versus LAPC9. Western blots of tumor extracts showed that the elevated imaging signal in CWR22 xenografts correlated with elevated levels of phosphorylated extracellular signal-regulated kinase 1/2 but not p38 or c-Jun NH2-terminal kinase. We conclude that a gene expression-based optical imaging system can accurately detect and quantify MAPK activity in live animals. (Cancer Res 2006; 66(22): 10778-85)
Inhibition of Prostate Tumor Growth and Bone Remodeling by the Vascular Targeting Agent VEGF121/rGel
Authors: Mohamedali Khalid A. , Poblenz Ann T. , Sikes Charles R. , Navone Nora M. , Thorpe Philip E. , Darnay Bryant G. , Rosenblum Michael G.
Published: November 2006

The pathophysiology of tumor growth following skeletal metastases and the poor response of this type of lesion to therapeutic intervention remains incompletely understood. Vascular endothelial growth factor (VEGF)-A and its receptors play a role in both osteoclastogenesis and tumor growth. Systemic (i.v.) treatment of nude mice bearing intrafemoral prostate (PC-3) tumors with the vascular ablative agent VEGF121/recombinant gelonin (rGel) strongly inhibited tumor growth. Fifty percent of treated animals had complete regression of bone tumors with no development of lytic bone lesions. Immunohistochemical analysis showed that VEGF121/rGel treatment suppressed tumor-mediated osteoclastogenesis in vivo. In vitro treatment of murine osteoclast precursors, both cell line (RAW264.7) and bone marrow–derived monocytes (BMM), revealed that VEGF121/rGel was selectively cytotoxic to osteoclast precursor cells rather than mature osteoclasts. VEGF121/rGel cytotoxicity was mediated by Flt-1, which was down-regulated during osteoclast differentiation. Analysis by flow cytometry and reverse transcription-PCR showed that both BMM and RAW264.7 cells display high levels of Flt-1 but low levels of Flk-1. Internalization of VEGF121/rGel into osteoclast precursor cells was suppressed by pretreatment with an Flt-1 neutralizing antibody or by placenta growth factor but not with an Flk-1 neutralizing antibody. Thus, VEGF121/rGel inhibits osteoclast maturation in vivo and it seems that this process is important in the resulting suppression of skeletal osteolytic lesions. This is a novel and unique mechanism of action for this class of agents and suggests a potentially new approach for treatment or prevention of tumor growth in bone. (Cancer Res 2006; 66(22): 10919-28)
Decreased NKX3.1 Protein Expression in Focal Prostatic Atrophy, Prostatic Intraepithelial Neoplasia, and Adenocarcinoma: Association with Gleason Score and Chromosome 8p Deletion
Authors: Bethel Carlise R. , Faith Dennis , Li Xiang , Guan Bin , Hicks Jessica L. , Lan Fusheng , Jenkins Robert B. , Bieberich Charles J. , De Marzo Angelo M.
Published: November 2006

NKX3.1 is a homeobox gene located at chromosome 8p21.2, and one copy is frequently deleted in prostate carcinoma. Prior studies of NKX3.1 mRNA and protein in human prostate cancer and prostatic intraepithelial neoplasia (PIN) have been conflicting, and expression in focal prostate atrophy lesions has not been investigated. Immunohistochemical staining for NKX3.1 on human tissue microarrays was decreased in most focal atrophy and PIN lesions. In carcinoma, staining was inversely correlated with Gleason grade. Fluorescence in situ hybridization showed that no cases of atrophy had loss or gain of 8p, 8 centromere, or 8q24 (C-MYC) and only 12% of high-grade PIN lesions harbored loss of 8p. By contrast, NKX3.1 staining in carcinoma was correlated with 8p loss and allelic loss was inversely related to Gleason pattern. Quantitative reverse transcription-PCR for NKX3.1 mRNA using microdissected atrophy revealed a concordance with protein in five of seven cases. In carcinoma, mRNA levels were decreased in 6 of 12 cases but mRNA levels correlated with protein levels in only 4 of 12 cases, indicating translational or post-translational control. In summary, NKX3.1 protein is reduced in focal atrophy and PIN but is not related to 8p allelic loss in these lesions. Therefore, whereas genetic disruption of NKX3.1 in mice leads to PIN, nongenetic mechanisms reduce NKX3.1 protein levels early in human prostate carcinogenesis, which may facilitate both proliferation and DNA damage in atrophic and PIN cells. Monoallelic deletions on chromosome 8p are associated with more advanced invasive and aggressive disease. (Cancer Res 2006; 66(22): 10683-90)
Improved Tumor Control through Circadian Clock Induction by Seliciclib, a Cyclin-Dependent Kinase Inhibitor
Authors: Iurisci Ida , Filipski Elisabeth , Reinhardt Jens , Bach Stéphane , Gianella-Borradori Athos , Iacobelli Stefano , Meijer Laurent , Lévi Francis
Published: November 2006

The circadian timing system and the cell division cycle are frequently deregulated in cancer. The therapeutic relevance of the reciprocal interactions between both biological rhythms was investigated using Seliciclib, a cyclin-dependent kinase (CDK) inhibitor (CDKI). Mice bearing Glasgow osteosarcoma received Seliciclib (300 mg/kg/d orally) or vehicle for 5 days at Zeitgeber time (ZT) 3, 11, or 19. On day 6, tumor mRNA 24-hour expression patterns were determined for clock genes (Per2, Rev-erbα, and Bmal1) and clock-controlled cell cycle genes (c-Myc, Wee1, cyclin B1, and CDK1) with quantitative reverse transcription-PCR. Affinity chromatography on immobilized Seliciclib identified CDK1/CDK2 and extracellular signal-regulated kinase (ERK) 1/ERK2, CDK7/CDK9, and casein kinase CK1ε as Seliciclib targets, which respectively regulate cell cycle, transcription, and circadian clock in Glasgow osteosarcoma. Seliciclib reduced tumor growth by 55% following dosing at ZT3 or ZT11 and by 35% at ZT19 compared with controls (P < 0.001). Tolerability was also best at ZT3. Mean transcriptional activity of Rev-erbα, Per2, and Bmal1 was arrhythmic in the tumors of untreated mice. Seliciclib induced rhythmic clock gene expression patterns with physiologic phase relations only after ZT3 dosing. c-Myc and Wee1 mRNAs displayed synchronous circadian rhythms in the tumors of control mice receiving vehicle only but not in those of mice given the drug. Seliciclib further enhanced Wee1 expression irrespective of dosing time, an effect that reinforced G2-M gating. Seliciclib also inhibited CK1ε, which determines circadian period length. The coordination of clock gene expression patterns in tumor cells was associated with best antitumor activity of Seliciclib. The circadian clock and its upstream regulators represent relevant targets for CDKIs. (Cancer Res 2006; 66(22): 10720-8)