bluuebunny/crossref_metadata_2025_split huggingface dataset:
MAIGO2 Is Involved in Exit of Seed Storage Proteins from the Endoplasmic Reticulum in Arabidopsis thaliana
Authors: Li Lixin , Shimada Tomoo , Takahashi Hideyuki , Ueda Haruko , Fukao Yoichiro , Kondo Maki , Nishimura Mikio , Hara-Nishimura Ikuko 
Published: December 2006

Abstract
Seed storage proteins are synthesized on the endoplasmic reticulum (ER) as precursors and then transported to protein storage vacuoles, where they are processed into mature forms. Here, we isolated an Arabidopsis thaliana mutant, maigo2 (mag2), that accumulated the precursors of two major storage proteins, 2S albumin and 12S globulin, in dry seeds. mag2 seed cells contained many novel structures, with an electron-dense core that was composed of the precursor forms of 2S albumin. 12S globulins were segregated from 2S albumin and were localized in the matrix region of the structures together with the ER chaperones lumenal binding protein and protein disulfide isomerase, which were more abundant in mag2 seeds. The MAG2 gene was identified as At3g47700, and the MAG2 protein had a RINT-1/TIP20 domain in the C-terminal region. We found that some MAG2 molecules were peripherally associated with the ER membrane. MAG2 had an ability to bind to two ER-localized t-SNAREs (for target-soluble NSF [N-ethylmaleimide–sensitive fusion protein] attachment protein receptor; At Sec20 and At Ufe1). Our findings suggest that MAG2 functions in the transport of storage protein precursors between the ER and Golgi complex in plants.
Reduction of Benzenoid Synthesis in Petunia Flowers Reveals Multiple Pathways to Benzoic Acid and Enhancement in Auxin Transport
Authors: Orlova Irina , Marshall-Colón Amy , Schnepp Jennifer , Wood Barbara , Varbanova Marina , Fridman Eyal , Blakeslee Joshua J. , Peer Wendy Ann , Murphy Angus S. , Rhodes David , Pichersky Eran , Dudareva Natalia 
Published: December 2006

Abstract
In plants, benzoic acid (BA) is believed to be synthesized from Phe through shortening of the propyl side chain by two carbons. It is hypothesized that this chain shortening occurs via either a β-oxidative or non-β-oxidative pathway. Previous in vivo isotope labeling and metabolic flux analysis of the benzenoid network in petunia (Petunia hybrida) flowers revealed that both pathways yield benzenoid compounds and that benzylbenzoate is an intermediate between l-Phe and BA. To test this hypothesis, we generated transgenic petunia plants in which the expression of BPBT, the gene encoding the enzyme that uses benzoyl-CoA and benzyl alcohol to make benzylbenzoate, was reduced or eliminated. Elimination of benzylbenzoate formation decreased the endogenous pool of BA and methylbenzoate emission but increased emission of benzyl alcohol and benzylaldehyde, confirming the contribution of benzylbenzoate to BA formation. Labeling experiments with 2H5-Phe revealed a dilution of isotopic abundance in most measured compounds in the dark, suggesting an alternative pathway from a precursor other than Phe, possibly phenylpyruvate. Suppression of BPBT activity also affected the overall morphology of petunia plants, resulting in larger flowers and leaves, thicker stems, and longer internodes, which was consistent with the increased auxin transport in transgenic plants. This suggests that BPBT is involved in metabolic processes in vegetative tissues as well.
KEEP ON GOING, a RING E3 Ligase Essential for Arabidopsis Growth and Development, Is Involved in Abscisic Acid Signaling
Authors: Stone Sophia L. , Williams Luis A. , Farmer Lisa M. , Vierstra Richard D. , Callis Judy 
Published: December 2006

Abstract
Analysis of the Arabidopsis thaliana RING-ANK (for Really Interesting New Gene-Ankyrin) family, a subgroup of RING-type E3 ligases, identified KEEP ON GOING (KEG) as essential for growth and development. In addition to the RING-HCa and ankyrin repeats, KEG contains a kinase domain and 12 HERC2-like repeats. The RING-HCa and kinase domains were functional in in vitro ubiquitylation and phosphorylation assays, respectively. Seedlings homozygous for T-DNA insertions in KEG undergo growth arrest immediately after germination, suggestive of increased abscisic acid (ABA) signaling, a major phytohormone that plays a key role in plant development and survival under unfavorable conditions. Here, we show that KEG is a negative regulator of ABA signaling. keg roots are extremely sensitive to the inhibitory effects of ABA and exhibit hypersensitivity to exogenous glucose, consistent with the known interaction between glucose and ABA signaling. The observations that KEG accumulates high levels of ABSCISIC ACID-INSENSITIVE5 (ABI5) without exogenous ABA, interacts with ABI5 in vitro, and that loss of ABI5 rescues the growth-arrest phenotype of keg mutant seedlings indicate that KEG is required for ABI5 degradation. In this capacity, KEG is central to ABA signaling by maintaining low levels of ABI5 in the absence of stress.
Genetic Characterization and Functional Analysis of the GID1 Gibberellin Receptors inArabidopsis
Authors: Griffiths Jayne , Murase Kohji , Rieu Ivo , Zentella Rodolfo , Zhang Zhong-Lin , Powers Stephen J. , Gong Fan , Phillips Andrew L. , Hedden Peter , Sun Tai-ping , Thomas Stephen G. 
Published: December 2006

AbstractWe investigated the physiological function of three Arabidopsis thaliana homologs of the gibberellin (GA) receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) by determining the developmental consequences of GID1 inactivation in insertion mutants. Although single mutants developed normally, gid1a gid1c and gid1a gid1b displayed reduced stem height and lower male fertility, respectively, indicating some functional specificity. The triple mutant displayed a dwarf phenotype more severe than that of the extreme GA-deficient mutant ga1-3. Flower formation occurred in long days but was delayed, with severe defects in floral organ development. The triple mutant did not respond to applied GA. All three GID1 homologs were expressed in most tissues throughout development but differed in expression level. GA treatment reduced transcript abundance for all three GID1 genes, suggesting feedback regulation. The DELLA protein REPRESSOR OF ga1-3 (RGA) accumulated in the triple mutant, whose phenotype could be partially rescued by loss of RGA function. Yeast two-hybrid and in vitro pull-down assays confirmed that GA enhances the interaction between GID1 and DELLA proteins. In addition, the N-terminal sequence containing the DELLA domain is necessary for GID1 binding. Furthermore, yeast three-hybrid assays showed that the GA-GID1 complex promotes the interaction between RGA and the F-box protein SLY1, a component of the SCFSLY1 E3 ubiquitin ligase that targets the DELLA protein for degradation.
Proteolytic Enzyme Activity During Storage of Radiation‐ Stabilized Raw Beef and Its Significance to Flavora
Authors: DRAKE MAURICE P. , GERNON GERALD D. , KRAUS FRED J. 
Published: December 2006

SUMMARYThis study has attempted to define the relationship of proteolysis to flavor during storage of irradiated raw beef. The data presented show that a decrease in consumer‐type taste‐panel preference during unrefrigerated storage of irradiated (4.5 megarad) raw ground beef correlates to some extent with the action of endocellular tissue proteolytic enzymes (cathepsins). The effective control of proteolytic activity using refrigerated storage is demonstrated. In the experiment cited, raw beef round steaks irradiated at a pasteurizing dose of 0.5 megarad were stable both microbiologically and enzymically, and the preference rating did not decline during six months at 3°C. The limited control of proteolysis during unrefrigerated storage using high‐pH beef is shown. The use of high‐pH beef for a limited extension of unrefrigerated storage life without significant decrease in preference rating is suggested. A need for further studies is indicated.
ON HOMOGENEOUS ANTIGENS AND ANTIBODIES. III. THE PREPARATION AND PROPERTIES OF THE UNIVALENT HAPTEN‐PROTEIN CONJUGATE PAPAIN‐S‐DNPL*
Authors: Brenneman L. , Singer S. J. 
Published: December 2006

SUMMARYKarl Landsteiner's introduction of the systematic study of hapten‐protein conjugates and antihapten antibodies was a great milestone in immunology and immunochemistry. His work, and the work of others following his lead, have illuminated the character of the antigen‐antibody interaction, and have provided antibodies whose specificities could be systematically varied and used in a wide variety of structural studies. It is important to recognize, however, that while conventionally prepared hapten‐protein conjugates are extraordinarily useful as model antigens for certain types of immunochemical studies, they may not be as simple immunogens as has generally been assumed. An adequate appreciation of the two structural considerations: a) that antibody‐combining sites are, generally, considerably larger than simple haptenic groups; and b) that hydrophobic haptens will tend to be immobilized on patches of the surface of the carrier molecule, leads to the realization that from an antigenic point of view, hapten‐protein conjugates may be, in fact, at least as complex and heterogeneous as are protein antigens themselves. Studies with such conjugates that ignore their complexities may come to erroneous conclusions about important immunological phenomena. The use of less heterogeneous or homogeneous hapten conjugates in these experiments may avoid, or at least minimize, such difficulties, and may also lead to the production of homogeneous antibodies useful for detailed chemical and structural studies.
Three-Dimensional Sharp Corner Displacement Functions for Bodies of Revolution
Authors: Huang C. S. , Leissa A. W. 
Published: December 2006

AbstractSharp corner displacement functions have been well used in the past to accelerate the numerical solutions of two-dimensional free vibration problems, such as plates, to obtain accurate frequencies and mode shapes. The present analysis derives such functions for three-dimensional (3D) bodies of revolution where a sharp boundary discontinuity is present (e.g., a stepped shaft, or a circumferential V notch), undergoing arbitrary modes of deformation. The 3D equations of equilibrium in terms of displacement components, expressed in cylindrical coordinates, are transformed to a new coordinate system having its origin at the vertex of the corner. An asymptotic analysis in the vicinity of the sharp corner reduces the equations to a set of coupled, ordinary differential equations with variable coefficients. By a suitable transformation of variables the equations are simplified to a set of equations with constant coefficients. These are solved, the boundary conditions along the intersecting corner faces are applied, and the resulting eigenvalue problems are solved for the characteristic equations and corner functions.
Buckling and
Sensitivity to Imperfection of Conical Shells Under Dynamic
Step-Loading
Authors: Jabareen Mahmood , Sheinman Izhak 
Published: December 2006

Abstract
A general nonlinear dynamic analysis, based on Donnell’s shell-type theory, is developed for an arbitrary imperfect isotropic conical shell. It is used for studying dynamic stability and imperfection sensitivity under dynamic step loading. The nonlinear dynamic time history and the sensitivity behavior are examined in parametric terms over a wide range of aspect ratios. A general symbolic code (using the MAPLE compiler) was programmed to create the differential operators. By this means the Newmark discretization, Galerkin procedure, Newton-Raphson iteration, and finite difference scheme are applied for automatic development of an efficient FORTRAN code for the parametric study, and for examining the correlation of the sensitivity behavior between two different dynamic stability criteria. An extensive parametric study of the effect of the cone semi-vertex angle on the stability and sensitivity to imperfection under dynamic step loading was carried out. It was found that the dynamic buckling can indeed be derived from the nonlinear static solution.
The Role of Fin
Geometry in Heat Sink Performance
Authors: Khan W.
A. , Culham J.
R. , Yovanovich M.
M. 
Published: December 2006

Abstract
The following study will examine the effect on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The use of entropy generation minimization, EGM, allows the combined effect of thermal resistance and pressure drop to be assessed through the simultaneous interaction with the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. The formulation for the dimensionless entropy generation rate is developed in terms of dimensionless variables, including the aspect ratio, Reynolds number, Nusselt number, and the drag coefficient. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters.
The β-Defensin Gallinacin-6 Is Expressed in the Chicken Digestive Tract and Has Antimicrobial Activity against Food-Borne Pathogens
Authors: van Dijk Albert , Veldhuizen Edwin J. A. , Kalkhove Stefanie I. C. , Tjeerdsma-van Bokhoven Johanna L. M. , Romijn Roland A. , Haagsman Henk P. 
Published: December 2006

ABSTRACT

Food-borne pathogens are responsible for most cases of food poisoning in developed countries and are often associated with poultry products, including chicken. Little is known about the role of β-defensins in the chicken digestive tract and their efficacy. In this study, the expression of chicken β-defensin gallinacin-6 (Gal-6) and its antimicrobial activity against food-borne pathogens were investigated. Reverse transcription-PCR analysis showed high expression of Gal-6 mRNA in the esophagus and crop, moderate expression in the glandular stomach, and low expression throughout the intestinal tract. Putative transcription factor binding sites for nuclear factor kappa beta, activator protein 1, and nuclear factor interleukin-6 were found in the Gal-6 gene upstream region, which suggests a possible inducible nature of the Gal-6 gene. In colony-counting assays, strong bactericidal and fungicidal activity was observed, including bactericidal activity against food-borne pathogens
Campylobacter jejuni
,
Salmonella enterica
serovar Typhimurium,
Clostridium perfringens
, and
Escherichia coli
. Treatment with 16 μg/ml synthetic Gal-6 resulted in a 3 log unit reduction in
Clostridium perfringens
survival within 60 min, indicating fast killing kinetics. Transmission electron microscopy examination of synthetic-Gal-6-treated
Clostridium perfringens
cells showed dose-dependent changes in morphology after 30 min, including intracellular granulation, cytoplasm retraction, irregular septum formation in dividing cells, and cell lysis. The high expression in the proximal digestive tract and broad antimicrobial activity suggest that chicken β-defensin gallinacin-6 plays an important role in chicken innate host defense.
Cumulative Effects of Several Nonenzymatic Mechanisms on the Resistance of
Pseudomonas aeruginosa
to Aminoglycosides
Authors: El'Garch Farid , Jeannot Katy , Hocquet Didier , Llanes-Barakat Catherine , Plésiat Patrick 
Published: December 2006

ABSTRACT

Screening of a Tn
5-
Hg insertional library (12,000 clones) constructed in wild-type
Pseudomonas aeruginosa
strain PAO1 identified four genes (namely,
galU
,
nuoG
,
mexZ
, and
rplY
) whose disruption individually led to increased resistance to aminoglycosides (means of twofold). Inactivation of these genes was associated with (i) impaired outer membrane uptake, (ii) reduced active transport, (iii) increased MexXY-OprM-mediated active efflux, and (iv) alteration of target of aminoglycosides, respectively. In addition, suppression of the gene
rplY
, which codes for ribosomal protein L25, was found to result in both moderate upregulation of the efflux system MexXY-OprM and hypersusceptibility to β-lactam antibiotics. Construction of double, triple, and quadruple mutants demonstrated cumulative effects of the different mechanisms on aminoglycoside resistance, with MICs increasing from 16- to 64-fold in the quadruple mutant compared to the wild-type strain PAO1. Altogether, these results illustrate how
P. aeruginosa
may gradually develop high resistance to these antibiotics via intrinsic (i.e., nonenzymatic) mechanisms, as in cystic fibrosis patients.
Impact of Empiric Antibiotic Therapy on Outcomes in Patients with
Pseudomonas aeruginosa
Bacteremia
Authors: Osih Regina B. , McGregor Jessina C. , Rich Shayna E. , Moore Anita C. , Furuno Jon P. , Perencevich Eli N. , Harris Anthony D. 
Published: December 2006

ABSTRACT

The impact of appropriate empirical antimicrobial therapy for
Pseudomonas aeruginosa
bacteremia on patient outcomes has not been clearly established. We assessed the effect of appropriate empirical therapy on in-hospital mortality and length of stay (LOS) among patients with
P. aeruginosa
bacteremia. This was a retrospective cohort study of inpatients with a positive blood culture for
P. aeruginosa
between January 2001 and June 2005. Empirical therapy was defined as appropriate if the patient received an antibiotic the organism was susceptible to between 8 h before culture collection and the time the susceptibility results were available. The severity of the illness was measured 24 h before culture collection. The data were analyzed using logistic regression (in-hospital mortality) and linear regression (LOS). Overall, there were 167 episodes of
P. aeruginosa
bacteremia, 123 (86%) of which received appropriate empirical antibiotics. Sixty-one patients died (36.5%). The median time from culture collection to susceptibility results was 3.4 days. After we adjusted for age, severity of illness, and time at risk, we found that the appropriate empirical therapy was not significantly associated with mortality (odds ratio = 0.96; 95% confidence interval = 0.31 to 2.93). There was a 7% reduction in the mean LOS for patients who had received appropriate therapy at the time susceptibility results were available compared to those who did not (
P
= 0.74). These data suggest that the use of appropriate empirical therapy, i.e., before susceptibility results are known may not be as critical to patient outcomes as other studies have suggested.
Flavonoid Dimers as Bivalent Modulators for Pentamidine and Sodium StiboglucanateResistance in
Leishmania
Authors: Wong Iris L. K. , Chan Kin-Fai , Burkett Brendan A. , Zhao Yunzhe , Chai Yi , Sun Hongzhe , Chan Tak Hang , Chow Larry M. C. 
Published: December 2006

ABSTRACT

Drug
resistance by overexpression of ATP-binding cassette (ABC) transporters
is an impediment in the treatment of leishmaniasis. Flavonoids are
known to reverse multidrug resistance (MDR) in
Leishmania
and
mammalian cancers by inhibiting ABC transporters. Here, we found that
synthetic flavonoid dimers with three (compound 9c) or four
(compound 9d) ethylene glycol units exhibited a significantly higher
reversing activity than other shorter or longer ethylene glycol-ligated
dimers, with ∼3-fold sensitization of pentamidine and sodium
stibogluconate (SSG) resistance in
Leishmania
, respectively.
This modulatory effect was dosage dependent and not observed in
apigenin monomers with the linker, suggesting that the modulatory
effect is due to its bivalent nature. The mechanism of reversal
activity was due to increased intracellular accumulation of pentamidine
and total antimony in
Leishmania
. Compared to other MDR
modulators such as verapamil, reserpine, quinine, quinacrine, and
quinidine, compounds 9c and 9d were the only agents that can reverse
SSG resistance. In terms of reversing pentamidine resistance, 9c and 9d
have activities comparable to those of reserpine and quinacrine.
Modulators 9c and 9d exhibited reversal activity on pentamidine
resistance among
LeMDR1
−/−
,
LeMDR1
+/+
, and
LeMDR1
-overexpressed mutants, suggesting that these modulators
are specific to a non-LeMDR1 pentamidine transporter. The
LeMDR1
copy number is inversely related to pentamidine
resistance, suggesting that it might be involved in importing
pentamidine into the mitochondria. In summary, bivalency could be a
useful strategy for the development of more potent ABC transporter
modulators and flavonoid dimers represent a promising reversal agent
for overcoming pentamidine and SSG resistance in parasite
Leishmania
.
Orally Administered Erythromycin in Rainbow Trout (
Oncorhynchus mykiss
): Residues in Edible Tissues and Withdrawal Time
Authors: Esposito Annarita , Fabrizi Laura , Lucchetti Dario , Marvasi Luigi , Coni Ettore , Guandalini Emilio 
Published: December 2006

ABSTRACT

Aquaculture production has notably increased in the last decades, mainly thanks to intensive farming. Together with market globalization, this gives rise to the spreading of several fish diseases, thus increasing the demand for veterinary drugs for aquatic species. Nonetheless, very few chemicals are registered for use in aquaculture, and fish farmers are often forced to resort to off-label use of drugs authorized for other food-producing animal species. Rainbow trout is the major farmed fish species in Italy and the second one in Europe. Erythromycin is the antibiotic of choice against gram-positive cocci, the major concern for trout farming, but it is not yet registered for aquaculture use in most European countries. The aim of this study was to follow the depletion of erythromycin in rainbow trout (
Oncorhynchus mykiss
), after its administration at 100 mg kg
−1
trout body weight day
−1
for 21 days through medicated feed (water temperature, 11.5°C). Erythromycin residues in fish muscle plus skin in natural proportion were determined by a validated liquid chromatography-electrospray ionization-tandem mass spectrometry method. Interpolation of our data, following European Agency for the Evaluation of Medicinal Products guidelines, gives a withdrawal time of 255°C-days (°C-day = water temperature × days), thus showing that the general value (500°C-day) recommended by the Council Directive (EEC) no. 82/2001 for off-label drug use in aquaculture would be too conservative in this case, with excessive costs for the farmers. Our study provides preliminary data for a more prudent use of erythromycin in rainbow trout, suggesting a possible withdrawal time after treatment.