bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Nature of Exocytosis in the Yolk Trophoblastic Layer of Silver Arowana (Osteoglossum bicirrhosum) Juvenile, the Representative of Ancient Teleost Fishes
Authors: Jaroszewska Marta , Dabrowski Konrad 
Published: September 2009

AbstractWe have chosen the silver arowana (Osteoglossum bicirrhosum), a representative of the most ancient teleost family Osteoglossidae, to address the question of yolk nutrients utilization. Silver arowana have particularly large eggs (1–1.5 cm of diameter) and a unique morphology of the yolk. We present evidence that the yolk cytoplasmic zone (ycz) in the “yolksac juveniles” is a very complex structure involved in sequential processes of yolk hydrolysis, lipoprotein particles synthesis, their transport, and exocytosis. Vacuoles filled with yolk granules in different stages of digestion move from the vitellolysis zone through the ycz to be emptied into the microvillar interspace in the process of exocytosis. The area of the ycz with the abundance of the mitochondria must play an important role in providing energy for both the transport of vacuoles and the release of their contents. Therefore, we postulate that the function of yolk syncytial layer (ysl) as the “early embryonic patterning center” transforms in fish larvae or yolksac juveniles into a predominantly specialized role as the yolk trophoblastic layer (ytl) involved in yolk nutrients utilization. In addition to discovering the mechanism of transformation of the ysl function into ytl function, we suggest that the machinery involved in nutrient mobilization and exocytosis in yolk of arowana yolksac juveniles can be very attractive system for studies of regulatory processes in almost all secretory pathways in animal cells. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.
The Normal Genital Tract of the Female California Sea Lion (Zalophus californianus): Cyclic Changes in Histomorphology and Hormone Receptor Distribution
Authors: Colegrove Kathleen M. , Gulland Frances M.D. , Naydan Diane K. , Lowenstine Linda J. 
Published: September 2009

AbstractChanges in reproductive tract histomorphology, and estrogen (ERα) and progesterone receptor (PR) expression throughout the breeding cycle were evaluated in free‐ranging stranded female California sea lions (Zalophus californianus). Hormone receptor expression in the ovaries, uterus, cervix, and vagina was evaluated using an immunohistochemical technique with monoclonal antibodies. During a large portion of the cycle, ovaries contained both a corpora lutea (CL) and follicles in varying stages of development. In the periods of pupping and estrus during June and July, and in the spring morphologic features of the endometrium suggested estrogen influence. There were areas of squamous differentiation in the pseudostratified columnar epithelium of the cervix and vagina in some animals during estrus and in the spring. Estrogen receptor immunohistochemical scores were highest during pupping and estrus and in the spring and lowest during embryonic diapause. Cyclic changes in uterine PR expression throughout the cycle were minimal. Both ERα and PR were expressed in epithelial and stromal cells throughout the cervix and vagina, however, receptor expression was typically higher in the stroma. Stromal cell hormone receptors may play an important role in epithelial responses to circulating sex hormones. The results of this investigation add to the general knowledge of California sea lion reproduction and establish baseline information on reproductive tract hormone receptors that will aid in determining the factors involved in urogenital cancer development in sea lions. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.
Neuroanatomy and Volumes of Brain Structures of a Live California Sea Lion (Zalophus californianus) From Magnetic Resonance Images
Authors: Montie Eric W. , Pussini Nicola , Schneider Gerald E. , Battey Thomas W.K. , Dennison Sophie , Barakos Jerome , Gulland Frances 
Published: September 2009

AbstractLateral view of MRI reconstruction of the brain surface of a California sea lion. The reconstruction placed in a parasagittal section through surrounding head structures. See Montie et al., on page 1523, in this issue.
Hedging unit‐linked life insurance contracts in a financial market driven by shot‐noise processes
Authors: Bi Junna , Guo Junyi 
Published: September 2009

AbstractWe consider the risk‐minimizing hedging problem for unit‐linked life insurance in a financial market driven by a shot‐noise process. Because the financial market is incomplete, the insurance claims cannot be hedged completely by trading stocks and bonds only, leaving some risk to the insurer. The theory of ((pseudo) locally) risk‐minimization is applied after a change of measure. Then the risk‐minimizing trading strategies and the associated intrinsic risk processes are determined for two types of unit‐linked contracts represented by the pure endowment and the term insurance. Copyright © 2009 John Wiley & Sons, Ltd.
Structure and function of the molecular chaperone Hsp104 from yeast
Authors: Grimminger‐Marquardt Valerie , Lashuel Hilal A. 
Published: September 2009

AbstractThe molecular chaperone Hsp104 plays a central role in the clearance of aggregates after heat shock and the propagation of yeast prions. Hsp104's disaggregation activity and prion propagation have been linked to its ability to resolubilize or remodel protein aggregates. However, Hsp104 has also the capacity to catalyze protein aggregation of some substrates at specific conditions. Hence, it is a molecular chaperone with two opposing activities with respect to protein aggregation. In yeast models of Huntington's disease, Hsp104 is required for the aggregation and toxicity of polyglutamine (polyQ), but the expression of Hsp104 in cellular and animal models of Huntington's and Parkinson's disease protects against polyQ and α‐synuclein toxicity. Therefore, elucidating the molecular determinants and mechanisms underlying the ability of Hsp104 to switch between these two activities is of critical importance for understanding its function and could provide insight into novel strategies aimed at preventing or reversing the formation of toxic protein aggregation in systemic and neurodegenerative protein misfolding diseases. Here, we present an overview of the current molecular models and hypotheses that have been proposed to explain the role of Hsp104 in modulating protein aggregation and prion propagation. The experimental approaches and the evidences presented so far in relation to these models are examined. Our primary objective is to offer a critical review that will inspire the use of novel techniques and the design of new experiments to proceed towards a qualitative and quantitative understanding of the molecular mechanisms underlying the multifunctional properties of Hsp104 in vivo. © 2009 Wiley Periodicals, Inc. Biopolymers 93:252–276, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Hsp70 molecular chaperones and Parkinson's disease
Authors: Witt Stephan N. 
Published: September 2009

AbstractBecause over expression of Hsp70 molecular chaperones suppresses the toxicity of aberrantly folded proteins that occur in Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis, and various polyQ‐diseases (Huntington's disease and ataxias), Hsp70 is garnering attention as a possible therapeutic agent for these various diseases. Here, I review progress in this fascinating field of molecular chaperones and neurodegeneration and describe our current understanding of the mechanisms by which Hsp70 protects cells from the PD‐related protein called alpha‐synuclein (α‐syn). © 2009 Wiley Periodicals, Inc. Biopolymers 93: 218–228, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
NMR studies of an immunomodulatory benzodiazepine binding to its molecular target on the mitochondrial F1F0‐ATPase
Authors: Stelzer Andrew C. , Frazee Richard W. , Van Huis Chad , Cleary Joanne , Opipari Anthony W. , Glick Gary D. , Al‐Hashimi Hashim M. 
Published: September 2009

AbstractBz‐423 is an inhibitor of the mitochondrial F1F0‐ATPase, with therapeutic properties in murine models of immune diseases. Here, we study the binding of a water‐soluble Bz‐423 analog (5‐(3‐(aminomethyl)phenyl)‐7‐chloro‐ 1‐methyl‐3‐(naphthalen‐2‐ylmethyl)‐1H‐benzo][e][1,4]diazepin‐2(3H)‐one); (1) to its target subunit on the enzyme, the oligomycin sensitivity conferring protein (OSCP), by NMR spectroscopy using chemical shift perturbation and cross‐relaxation experiments. Titration experiments with constructs representing residues 1–120 or 1–145 of the OSCP reveals that (a) 1 binds to a region of the protein, at the minimum, comprising residues M51, L56, K65, V66, K75, K77, and N92, and (b) binding of 1 induces conformational changes in the OSCP. Control experiments employing a variant of 1 in which a key binding element on the small molecule was deleted; it had no perturbational effect on the spectra of the OSCP, which indicates that the observed changes with 1 represent specific binding interactions. Collectively, these data suggest that 1 might inhibit the enzyme through an allosteric mechanism where binding results in conformational changes that perturb the OSCP‐F1 interface resulting in disrupted communication between the peripheral stalk and the F1‐domain of the enzyme. © 2009 Wiley Periodicals, Inc. Biopolymers 29: 85–92, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Activation of lactoperoxidase by heme‐linked protonation and heme‐independent iodide binding
Authors: Toyama Akira , Tominaga Aya , Inoue Tatsuo , Takeuchi Hideo 
Published: September 2009

AbstractLactoperoxidase (LPO), a mammalian secretory heme peroxidase, catalyzes the oxidation of thiocyanate by hydrogen peroxide to produce hypothiocyanate, an antibacterial agent. Although LPO is known to be activated at acidic pH and in the presence of iodide, the structural basis of the activation is not well understood. We have examined the effects of pH and iodide concentration on the catalytic activity and the structure of LPO. Electrochemical and colorimetric assays have shown that the catalytic activity is maximized at pH 4.5. The heme Soret absorption band exhibits a small red‐shift at pH 5.0 upon acidification, which is ascribable to a structural transition from a neutral to an acidic form. Resonance Raman spectra suggest that the heme porphyrin core is slightly contracted and the Fe‐His bond is strengthened in the acidic form compared to the neutral form. The structural change of LPO upon activation at acidic pH is similar to that observed for myeloperoxidase, another mammalian heme peroxidase, upon activation at neutral pH. Binding of iodide enhances the catalytic activity of LPO without affecting either the optimum pH of activity or the heme structure, implying that the iodide binding occurs at a protein site away from the heme‐linked protonation site. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 113–120, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
A novel alginate hollow fiber bioreactor process for cellular therapy applications
Authors: Hoesli Corinne A. , Luu Minh , Piret James M. 
Published: September 2009

AbstractGel‐matrix culture environments provide tissue engineering scaffolds and cues that guide cell differentiation. For many cellular therapy applications such as for the production of islet‐like clusters to treat Type 1 diabetes, the need for large‐scale production can be anticipated. The throughput of the commonly used nozzle‐based devices for cell encapsulation is limited by the rate of droplet formation to ∼0.5 L/h. This work describes a novel process for larger‐scale batch immobilization of mammalian cells in alginate‐filled hollow fiber bioreactors (AHFBRs). A methodology was developed whereby (1) alginate obstruction of the intra‐capillary space medium flow was negligible, (2) extra‐capillary alginate gelling was complete and (3) 83 ± 4% of the cells seeded and immobilized were recovered from the bioreactor. Chinese hamster ovary (CHO) cells were used as a model aggregate‐forming cell line that grew from mostly single cells to pancreatic islet‐sized spheroids in 8 days of AHFBR culture. CHO cell growth and metabolic rates in the AHFBR were comparable to small‐scale alginate slab controls. Then, the process was applied successfully to the culture of primary neonatal pancreatic porcine cells, without significant differences in cell viability compared with slab controls. As expected, alginate‐immobilized culture in the AHFBR increased the insulin content of these cells compared with suspension culture. The AHFBR process could be refined by adding matrix components or adapted to other reversible gels and cell types, providing a practical means for gel‐matrix assisted cultures for cellular therapy. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Asymmetrically simultaneous synthesis of L‐homophenylalanine and N6‐protected‐2‐oxo‐6‐amino‐hexanoic acid by engineered Escherichia coli aspartate aminotransferase
Authors: Lo Hsueh‐Hsia , Lin Wei‐De , Hsu Shih‐Kuang , Hsu Wen‐Hwei 
Published: September 2009

AbstractL‐Homophenylalanine (L‐HPA) and N6‐protected‐2‐oxo‐6‐amino‐hexanoic acid (N6‐protected‐OAHA) can be used as building blocks for the manufacture of angiotensin‐converting enzyme inhibitors. To synthesize L‐HPA and N6‐protected‐OAHA simultaneously from 2‐oxo‐4‐phenylbutanoic acid (OPBA) and N6‐protected‐L‐lysine, several variants of Escherichia coli aspartate aminotransferase (AAT) were developed by site‐directed mutagenesis and their catalytic activities were investigated. Three kinds of N6‐protected‐L‐lysine were tested as potential amino donors for the bioconversion process. AAT variants of R292E/L18H and R292E/L18T exhibited specific activities of 0.70±0.01 U/mg protein and 0.67±0.02 U/mg protein to 2‐amino‐6‐tert‐butoxycarbonylamino‐hexanoic acid (BOC‐lysine) and 2‐amino‐6‐(2,2,2‐trifluoro‐acetylamino)‐hexanoic acid, respectively. E. coli cells expressing R292E/L18H variant were able to convert OPBA and BOC‐lysine to L‐HPA and 2‐oxo‐6‐tert‐butoxycarbonylamino‐hexanoic acid (BOC‐OAHA) with 96.2% yield in 8 h. This is the first report demonstrating a process for the simultaneous production of two useful building blocks, L‐HPA and BOC‐OAHA. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Microbial Reactions on 7α‐Hydroxyfrullanolide and Evaluation of Biotransformed Products for Antibacterial Activity
Authors: Ata Athar , Betteridge Jordan , Schaub Emmanuel , Kozera Daniel J. , Holloway Paul , Samerasekera Radhika 
Published: September 2009

Abstract7α‐Hydroxyfrullanolide (1), a known sesquiterpenoid, was isolated from Sphaeranthus indicus using an antibacterial‐activity‐directed fractionation method. This compound had exhibited a significant antibacterial activity against Gram‐positive bacteria. Chemical and microbial reactions were performed to prepare eight different analogues of compound 1 in order to evaluate these newly synthesized compounds for antibacterial activity. These compounds were 1β,7α‐dihydroxyfrullanolide (2), 7α‐hydroxy‐1‐oxofrullanolide (3), 4,5‐dihydro‐7α‐hydroxyfrullanolide (4), 11,13‐dihydro‐7α‐hydroxyfrullanolide (5), 13‐acetyl‐7α‐hydroxyfrullanolide (6), 2α,7α‐dihydroxysphaerantholide (7), 4α,5α‐epoxy‐7α‐hydroxyfrullanolide (8), and 4β,5β‐epoxy‐7α‐hydroxyfrullanolide (9). Microbial reactions on 1 using whole‐cell cultures of Cunninghamella echinulata and Curvularia lunata yielded compounds 2–4. Incubation of compound 1 with the liquid cultures of Apsergillus niger and Rhizopus circinans yielded metabolites 5–7, while 8 and 9 were prepared by carrying out an epoxidation reaction on 1 using meta‐chloroperbenzoic acid (mCPBA). Structures of compounds 2–9 were elucidated with the aid of extensive NMR spectral studies. Compounds 2–4 were found to be new metabolites. Compounds 1–9 were evaluated for antibacterial activity and found to exhibit a wide range of bioactivities. Antibacterial‐activity data of 1–9 suggested that the bioactivity of 1 is largely due to the presence of C(4)C(5), C(11)C(13), and a γ‐lactone moiety.
Selected Thoughts on Chiral Crystals, Chiral Surfaces, and Asymmetric Heterogeneous Catalysis
Authors: Harris Kenneth D. M. , Thomas Sir John Meurig 
Published: September 2009

AbstractAlthough the uses of zeolitic materials in heterogeneous catalysis are extensive, the opportunity to develop applications of zeolites in enantioselective catalysis remains underexploited. In part, the relative paucity of chiral zeolite structures is one underlying reason, although some significant progress has been made in recent years in the preparation and structural characterization of chiral zeolitic materials, including the recent report of ITQ‐37, the first example of a chiral mesoporous zeolite. However, as elaborated in this Minireview article, the preparation of a chiral zeolite structure is itself not sufficient to ensure that the material will be useful in enantioselective catalysis, and a number of other key issues must also be addressed. In addition to highlighting these issues, this Minireview surveys more widely a number of concepts that are pivotal to the design of chiral solids for the catalysis of enantioselective transformations. In addition to chiral zeolites, a range of other chiral materials, including organic molecular solids, and chiral catalysts, including metal–organic frameworks, chiral metal surfaces, and single‐site immobilized organometallic species, are discussed, together with an appraisal of future directions for asymmetric heterogeneous catalysis.
Cyanide Detoxification of Mining Wastewaters with TiO2 Nanoparticles and Its Recovery by Electrocoagulation
Authors: Parga J. R. , Vázquez V. , Casillas H. M. , Valenzuela J. L. 
Published: September 2009

AbstractDue to the widespread use of cyanide in mining operations, its recovery and destruction is important for both the environmental aspects of wastewater and its treatment, and the economic aspects associated with the high consumption of chemicals by the process itself. A photoelectrocatalytic detoxification technique with titanium dioxide microelectrodes is one of the most innovative ways for the treatment of wastewater containing cyanide. However, this technique has a disadvantage for industrial application in that the separation of titanium dioxide after the photocatalytic degradation of cyanide is rather difficult due to the fineness of the particles, and therefore, the reuse of the titanium dioxide has not been attained for the treatment of cyanide‐containing wastewater. To overcome this weak point, an electrocoagulation (EC) technique is used to recover the titanium dioxide from its aqueous suspensions. The results show that photodegradation of cyanide is 93 % in 30 min using a 450 W halogen lamp. The recovery of anatase with the EC process is 98 %. The results indicate that this technique has the potential to serve as a reliable and economical method because sunlight can be used efficiently as the power source. The Langmuir isotherm is used to obtain the thermodynamic parameters, i.e., free energy, enthalpy and entropy. The evaluation of these parameters, i.e., ΔG° = –37 kJ/mol, ΔH° = –54 kJ/mol and ΔS° = 0.524 kJ/mol K, indicates the spontaneous and exothermic nature of the adsorption of the anatase particles on the iron species.
Determination of Diffusivity From Steady‐state Mass Transfer Measurements in a Continuous Dialyzer Under Conditions of Non‐zero Solution Flux Through a Membrane
Authors: Palatý Z. , Bendová H. 
Published: September 2009

AbstractThe transport of selected inorganic acids (HCl, H3PO4) through an anion‐exchange membrane, Neosepta‐AFN, was investigated in a two‐compartment counter‐current continuous dialyzer with single passes at steady state. The basic data obtained were completed by the measurement of sorption isotherms. The mass transfer rate of the individual acids was quantified by the diffusivity of acid in the membrane, which was determined from the acid concentrations in the streams entering and leaving the dialyzer. For this purpose, two ordinary differential equations describing the steady‐state concentration profiles of acid in both the compartments of the dialyzer were numerically solved in connection with an optimizing procedure. In the mathematical model used, the mass transfer resistances in the liquid films on both sides of the membrane and the flux of solution through the membrane were taken into account. All the experiments, carried out at a constant temperature of 25 °C with subsequent data treatment, revealed that the diffusivity of hydrochloric acid is about one order of magnitude higher than that of phosphoric acid. Moreover, regarding the dependence of the diffusivity of hydrochloric acid upon its concentration in the membrane, a maximum at an acid concentration of 0.622 kmol/m3 can be identified, while the diffusivity of phosphoric acid remains practically constant.
A Self‐Assembled Foldamer Capsule: Combining Single and Double Helical Segments in One Aromatic Amide Sequence
Authors: Bao Chunyan , Gan Quan , Kauffmann Brice , Jiang Hua , Huc Ivan 
Published: September 2009

AbstractIn this manuscript, we present supramolecular capsules based on a new design relying on both self‐assembly and folding of oligomeric strands. We have designed an aromatic amide foldamer in which each monomer encodes three levels of information: a specific cavity size, recognition groups for guest binding, and a propensity to adopt a single or a double helical motif. Thus, a tetradecameric sequence based on four different monomers was encoded so that a wide double helical segment resulting from the hybridization of two strands creates a cavity in which guests, such as 1,10‐decanediol, can be bound. Additionally two narrow single helical segments form end‐caps and isolate the guest from the solvent. The design, synthesis, solid‐state and solution‐state characterization of duplex formation and guest binding are presented.
General Access to Aminobenzyl‐o‐carboranes as a New Class of Carborane Derivatives: Entry to Enantiopure Carborane–Amine Combinations
Authors: Terrasson Vincent , Planas José Giner , Prim Damien , Teixidor Francesc , Viñas Clara , Light Mark E. , Hursthouse Michael B. 
Published: September 2009

AbstractThe convenient synthesis of original aminobenzyl‐o‐carboranes, which represent a new class of nitrogenated carborane derivatives, is described. These novel compounds have been efficiently prepared starting from commercially available aromatic aldehydes and monosubstituted o‐carboranes via carboranyl alcohols and chlorides as intermediates. The key step of this methodology is a selective nucleophilic amination under mild conditions that allows the formation of the expected amines while limiting the partial deboronation of the carborane cluster. This general strategy has been applied to the preparation of a wide variety of aminobenzyl‐o‐carboranes. The extension of this pathway to the synthesis of enantiopure carborane–amine combinations is also described.