bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Conformational Switches: From Nature to Design
Authors: Ha Jeung‐Hoi , Loh Stewart N.
Published: June 2012

Protein conformational switches alter their shape upon receiving an input signal, such as ligand binding, chemical modification, or change in environment. The apparent simplicity of this transformation—which can be carried out by a molecule as small as a thousand atoms or so—belies its critical importance to the life of the cell as well as its capacity for engineering by humans. In the realm of molecular switches, proteins are unique because they are capable of performing a variety of biological functions. Switchable proteins are therefore of high interest to the fields of biology, biotechnology, and medicine. These molecules are beginning to be exploited as the core machinery behind a new generation of biosensors, functionally regulated enzymes, and “smart” biomaterials that react to their surroundings. As inspirations for these designs, researchers continue to analyze existing examples of allosteric proteins. Recent years have also witnessed the development of new methodologies for introducing conformational change into proteins that previously had none. Herein we review examples of both natural and engineered protein switches in the context of four basic modes of conformational change: rigid‐body domain movement, limited structural rearrangement, global fold switching, and folding–unfolding. Our purpose is to highlight examples that can potentially serve as platforms for the design of custom switches. Accordingly, we focus on inducible conformational changes that are substantial enough to produce a functional response (e.g., in a second protein to which it is fused), yet are relatively simple, structurally well‐characterized, and amenable to protein engineering efforts.
Seven New Sesquiterpenes from Cultures of the Basidiomycete Conocybe siliginea
Authors: Yang Xiaoyan , Feng Tao , Yin Xia , Li Zhenghui , Zhang Lin , Liu Jikai
Published: June 2012

Seven new tremulane‐type sesquiterpenes (1–7) have been isolated from cultures of the basidiomycete Conocybe siliginea. Their structures and relative configurations were elucidated by extensive spectroscopic data (HSQC, HMBC, 1H‐1H COSY, ROESY) and MS analysis.
Four New 9,19‐Cyclolanostane Triterpenes from the Rhizomes of Cimicifuga foetida Collected in Yulong
Authors: Wang Haiyan , Nian Yin , Ma Chengyou , Liu Jieqing , Song Yanbo , Zhou Lin , Qiu Minghua
Published: June 2012

Four new 9,19‐cyclolanostane‐type triterpenes (1–4), were isolated from the rhizomes of Cimicifuga foetida. On the basis of spectroscopic analysis, their chemical structures were elucidated as 1,7‐dien‐cimigenol‐3,12‐dione (1), 1‐en‐cimigenol‐3,11‐dione (2), 11(‐hydroxy‐7‐en‐cimigenol‐3‐one (3), and (20R,24R)‐24,25‐epoxy‐11(‐hydroxy‐7‐en‐9,19‐cyclolanost‐3,16,23‐trione (4).
An Improved Practical Route to (±)‐Epibatidine through L‐Proline Catalyzed Intramolecular Michael Addition
Authors: Huang Xiangui , Shi Hongwei , Ren Jiangmeng , Liu Guixia , Tang Yun , Zeng Bubing
Published: June 2012

This paper describes a rapid and practical synthetic route involving six‐step reactions towards the diastereoselectively synthesis of (±)‐endo‐Epibatidine, starting from 6‐chloro‐3‐pyridinecarboxaldehye. The effective Henry reaction gave precursor (E)‐6‐(6‐chloropyridin‐3‐yl)‐5‐nitrohex‐5‐en‐2‐one (3a) which could be used in the next step. Various benzoic acid derivatives were used to optimize intramolecular Michael addition of ketone to pyridinylnitroolefins to provide the key intermediate 3‐(6‐chloropyridin‐3‐yl)‐4‐nitrocyclohexanone ((±)‐7a) with high yield.
Three New β‐Resorcylic Acid Lactones from Paecilomyces sp. SC0924
Authors: Xu Liangxiong , Xue Jinghua , Zou Yong , He Shujie , Wei Xiaoyi
Published: June 2012

Three new β‐resorcylic acid lactones (RALs), paecilomycins G–I (1–3), and eight known compounds, aigialomycins B–D (4–6), 1′,2′‐epoxy aigialomycin D (7), zearalenone (8), 7′‐dehydrozearalenone (9), and trans‐7′,8′‐dehydrozearalenol (10), antibiotic LL‐Z1640‐1 (11), were isolated from the mycelial solid culture of Paecilomyces sp. SC0924. Their structures were established by spectroscopic methods and chemical means. In an assessment of antifungal activity by the well plate diffusion method, five known RALs, 4–7 and 11 showed weak activities against Peronophythora litchii
Logically Sensing Aggregate Process and Discriminating SDS from Other Surfactants with the Assistance of BSA
Authors: Qian Junhong , Xu Yufang , Qian Xuhong
Published: June 2012

An amphiphilic fluorescent probe, 3‐dodecylamino dihydrogen imidazo[2,1‐α]benz[de]isoquinolin‐7‐one (compound 3), was used to sense the aggregate formation process of bovine serum albumine (BSA), sodium dodecyl sulfate (SDS) and their mixed system. The fluorescence intensity of 3 was significantly affected by the adding order of SDS and BSA, and SDS can be distinguished from other surfactants with the aid of BSA, but only when 3 is allowed to interact with BSA first. The results revealed that compound 3 is preferentially sited in the hydrophobic region of BSA, and thermodynamically in SDS‐BSA mixed aggregate. Sodium phosphate buffer solution (PBS) and BSA played important but distinct roles in distinguishing SDS micelle from the others.
Connecting developmental trajectories: Biases in face processing from infancy to adulthood
Authors: Scherf K. Suzanne , Scott Lisa S.
Published: June 2012

The nature of the developmental trajectory of face recognition abilities from infancy through adulthood is multifaceted and currently not well understood. We argue that the understanding of this trajectory can be greatly informed by taking a more functionalist approach in which the influence of age‐appropriate developmental tasks and goals are considered. To build this argument, we provide a focused review of developmental change across several important biases within face processing (species, race, age, and gender biases) from infancy through adulthood. We show that no existing theoretical framework can simultaneously and parsimoniously explain these very different trajectories and relative degrees of plasticity. We offer several examples of infant‐ and adolescent‐specific developmental tasks that we predict have an essential influence on the content and description of information that individuals need to extract from faces at these very different developmental stages. Finally, we suggest that this approach may provide a unique opportunity to study the role of early experience in (i.e., age of acquisition effects) and the quality and range of experiences that are critical for shaping behaviors through the course of development, from infancy to adulthood. © 2012 Wiley Periodicals,Inc. Dev Psychobiol 54: 643–663, 2012.
Early experience shapes vocal neural coding and perception in songbirds
Authors: Woolley Sarah M. N.
Published: June 2012

Songbirds, like humans, are highly accomplished vocal learners. The many parallels between speech and birdsong and conserved features of mammalian and avian auditory systems have led to the emergence of the songbird as a model system for studying the perceptual mechanisms of vocal communication. Laboratory research on songbirds allows the careful control of early life experience and high‐resolution analysis of brain function during vocal learning, production, and perception. Here, I review what songbird studies have revealed about the role of early experience in the development of vocal behavior, auditory perception, and the processing of learned vocalizations by auditory neurons. The findings of these studies suggest general principles for how exposure to vocalizations during development and into adulthood influences the perception of learned vocal signals. © 2012 Wiley Periodicals,Inc. Dev Psychobiol 54: 612–631, 2012.
Importing the homology concept from biology into developmental psychology
Authors: Moore David S.
Published: June 2012

To help introduce the idea of homology into developmental psychology, this article presents some of the concepts, distinctions, and guidelines biologists and philosophers of biology have devised to study homology. Some unresolved issues related to this idea are considered as well. Because homology reflects continuity across time, developmental scientists should find this concept to be useful in the study of psychological/behavioral development, just as biologists have found it essential in the study of the evolution and development of morphological and other characteristics. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 13–21, 2013.
Homology, correspondence, and continuity across development: The case of sleep
Authors: Blumberg Mark S.
Published: June 2012

The causal relationships among developing behaviors can take many forms. At one extreme, two behaviors may emerge independently of one another and, at the other extreme, the emergence of one behavior may depend on the prior emergence of the other. Whether the two behaviors in the latter case should be designated as developmentally homologous is explored in this essay by reviewing differing approaches to conceptualizing the development of sleep. It is argued that whereas the concept of developmental homology may offer little new to the understanding of sleep development, the conventional notion of evolutionary homology remains to be fully exploited. Identifying homologous sleep processes will benefit from the adoption of a developmental comparative approach that emphasizes real‐time sleep dynamics and individual sleep components. Because evolution occurs through the modification of developmental processes, a new commitment to a developmental comparative approach to sleep is a necessary next step toward a better understanding of its evolution. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 92–100, 2013.
“Ménage à trois”: the presence/absence of thyme shapes the mutualistic interaction between the host plant Medicago truncatula (Fabaceae) and its symbiotic bacterium Sinorhizobium meliloti
Authors: Ehlers Bodil K. , Grøndahl Eva , Ronfort Joëlle , Bataillon Thomas
Published: June 2012

The long‐term maintenance of specialized mutualisms remains an evolutionary puzzle. Recent focus has been on factors governing the stability of these mutualisms, including sanctions by the host, partner choice, and coevolutionary constraint, that is, the genetic correlation (rG) between fitness of both partners. So far these studies have been typically carried out in a single environment. Here, we ask if the genetic correlation between fitness of the host plant Medicago truncatula (Fabaceae) and its bacterial symbiont Sinorhizobium meliloti is affected by the presence/absence of a monoterpene (carvacrol) leached into the soil by Thymus vulgaris—a common plant of the Mediterranean vegetation, often co‐occuring with Medicago. We show that the presence of carvacrol in the soil dramatically affects fitness of the rhizobial partner and increases the magnitude of rG between plant and rhizobia fitness (rG= 0.02 ± 0.05 vs. rG= 0.57 ± 0.02). This finding emphasizes the importance of heterogeneity in the biotic environment for understanding the evolution of species interactions.
Interfamily variation in amphibian early life‐history traits: raw material for natural selection?
Authors: Hopkins Gareth R. , Gall Brian G. , French Susannah S. , Brodie Edmund D.
Published: June 2012

The embryonic development and time to hatching of eggs can be highly adaptive in some species, and thus under selective pressure. In this study, we examined the underlying interfamily variation in hatching timing and embryonic development in a population of an oviparous amphibian, the rough‐skinned newt (Taricha granulosa). We found significant, high variability in degree of embryonic development and hatching timing among eggs from different females. Patterns of variation were present regardless of temperature. We also could not explain the differences among families by morphological traits of the females or their eggs. This study suggests that the variation necessary for natural selection to act upon is present in the early life history of this amphibian.
Syk‐dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization
Authors: Gasparrini Francesca , Molfetta Rosa , Quatrini Linda , Frati Luigi , Santoni Angela , Paolini Rossella
Published: June 2012

Several lines of evidence suggest that Syk controls immune receptor endocytic trafficking. However, the Syk substrates that regulate this process are not currently known. Here, we demonstrate that Syk knockdown prevents the trafficking of engaged high affinity IgE receptor (FcεRI) to a degradative compartment in mast cells. We then concentrate our attention on hepatocyte growth factor‐regulated tyrosine kinase substrate (Hrs) as potential Syk substrate, since it serves as critical regulator for FcεRI entry into lysosomes. We show that Hrs undergoes antigen‐dependent tyrosine phosphorylation and ubiquitination, and identify Syk as the kinase responsible for Hrs phosphorylation. Syk was also required for Hrs ubiquitination catalyzed by c‐Cbl E3 ligase. Syk‐dependent regulation of Hrs covalent modifications, without affecting protein stability, controlled Hrs localization. The majority of phosphorylated Hrs forms were observed only in membrane compartments, whereas ubiquitinated Hrs was predominantly cytosolic, suggesting that both modifications might impact on Hrs function. Together, these findings provide a major step forward in understanding how Syk orchestrates endocytosis of engaged immune receptors.
Phytosterols in pumpkin seed oil extracted by organic solvents and supercritical CO2
Authors: Hrabovski Nataša , Sinadinović‐Fišer Snežana , Nikolovski Branislava , Sovilj Milan , Borota Olga
Published: June 2012

Phytosterols in Cucurbita pepo convar. citrullina seed oil were analyzed by GC–MS after extraction by the organic solvents, hexane and petroleum ether, and by supercritical carbon dioxide at 400 bar and 40°C. Desmosterol, campesterol, stigmasterol, β‐sitosterol, spinasterol, Δ7,22,25‐stigmastatrienol, Δ7‐stigmastenol, Δ7,25‐stigmastadienol, and Δ7‐avenasterol were identified mass spectrometrically via detection of the parent molecular ions and fragmentation patterns of corresponding trimethylsilyl derivatives. The used derivatizing agents N‐methyl‐N‐(trimethylsilyl)trifluoroacetamide (MSTFA) and N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA) are equally effective for phytosterol content determination. As expected, the predominant phytosterols were Δ7‐sterols that ranged from 91.0 to 94.2% of the total phytosterol content given as sum of free sterols and steryl esters. Comparison of extraction methods revealed that, although the oil yields obtained by extraction with hexane, petroleum ether and supercritical CO2 were 43.37, 44.65, and 36.17%, respectively, the total phytosterol content in supercritical CO2 extract (294 mg/100 g oil, for both MSTFA and BSTFA) was about 30% higher than in hexane and about 20% higher than in petroleum ether extract.

Practical applications: Extraction with the application of fluids in supercritical state opens a new approach to the production of edible vegetable oils. Many economical, health, and environmental aspects are interlaced in this modern approach. By applying the supercritical extraction, the selectivity of the extraction can be significantly improved compared to traditional methods of extraction. Thus, depending on the operating conditions of supercritical CO2 extraction higher total phytosterol content can be achieved resulting in improved nutritional value of the pumpkin seed oil.
Soybean oil‐based polyurethane networks as candidate biomaterials: Synthesis and biocompatibility
Authors: Miao Shida , Sun Lijing , Wang Ping , Liu Ruina , Su Zhiguo , Zhang Songping
Published: June 2012

Biobased polymeric materials are gaining increasing attention in biomedical areas. Here, we report a new class of biocompatible polyurethanes prepared from soybean oil‐based polyol that was synthesized by ring‐opening reaction of epoxidized monoglyceride (EMG) with lactic acid. By adjusting the molar ratio of hydroxyl to isocyanate group and the content of chain extender, soybean oil‐based polyurethanes with tensile strength of 9.30–27.1 MPa and elongation at break of 74.1–110.7% were prepared, while usual lipid‐based polyurethanes with the same 1,6‐diisocyanatohexane as reactant hardly have tensile strength higher than 5 MPa. Mouse fibroblast cells (L‐929) showed good adhesion and growth behavior on the polyurethane samples with more hydrophilic surfaces, and the cell viabilities of more than 50% were achieved with commercial tissue culture polystyrene (TCPS) disk as control. The good mechanical property and biocompatibility of the soybean oil‐based polyurethanes will make them suitable for wide range of potential biomedical applications.

Practical applications: The synthesized soybean oil‐based polyurethanes have adjustable tensile strengths from 9.30–27.1 MPa and elongation at break of 74.1–110.7%. Along with their good biocompatibility, the polyurethanes can potentially replace wide range of part of petroleum‐based polymeric materials, particularly as biomedical materials.
Synthesis of a Naphthalene‐diimide Cyclophane for Tuning Supramolecular Interactions by Metal Ions
Authors: Yu Yanwen , Li Yongjun , Chen Songhua , Liu Taifeng , Qin Zhihong , Liu Huibiao , Li Yuliang
Published: June 2012

A new supramolecular species of naphthalene‐diimide cyclophane containing triazole units was synthesized, and its fluorescent responses to metal ions were investigated in dichloromethane (DCM). The fluorescence emission of NDI was quenched by intramolecular electron transfer, whereas the appearance of dimer emission of the naphthalene‐diimide in the presence of Mg2+, Ba2+, Hg2+, Ca2+, Zn2+ and Pb2+ was observed.
Synthesis of 2,6‐Bis(oxazolyl)pyridine Ligands for Luminescent LnIII Complexes
Authors: Pereira Goreti , Ferreira Miguel F. , Castanheira Elisabete M. S. , Martins José A. , Ferreira Paula M. T.
Published: June 2012

New bis(oxazolyl)pyridine ligands for LnIII ions were prepared by using an expeditious methodology from threonine and dipicolinic chloride. The synthetic strategy includes a dehydration step to give a bis(dehydroaminobutyric acid) derivative followed by bromination and cyclization with DBU. Photophysical studies of EuIII and TbIII complexes of these ligands showed that the 2,6‐bis(oxazolyl)pyridine moiety acts as an effective sensitizer for lanthanide luminescence and indicate the formation of 3:1 complexes [Ln{bis(oxazole)pyridine}3]3+.
Analysis of the Electrochemical Oxidation of Multiwalled Carbon Nanotube Tower Electrodes in Sodium Hydroxide
Authors: Doepke Amos , Han Changseok , Back Tyson , Cho Wondong , Dionysiou Dionysios D. , Shanov Vesselin , Halsall H. Brian , Heineman William R.
Published: June 2012

Towers of aligned multiwalled carbon nanotubes (MWCNTs) were electrochemically oxidized in aqueous 1 M NaOH. An oxidation current that decayed with time was monitored using amperometry at a fixed potential. Cyclic voltammetry showed that the background current and electrode capacitance increased after oxidation without significantly affecting the faradaic current from the reduction of ferricyanide. Oxidation in NaOH caused morphological changes and increased hydrophilicity of the MWCNT tower electrodes. XPS spectra indicated increased oxygen on the surface after oxidation, while Raman spectra indicated that a large amount of amorphous carbon was present before and after oxidation.
Relationships between the Seasonal Variations of Macroinvertebrates, and Land Uses for Biomonitoring in the Xitiaoxi River Watershed, China
Authors: Zhang Yong , Wang Beixin , Han Minghua , Wang Lizhu
Published: June 2012

The impacts of differences in watershed land uses, and differences in seasonality on benthic macroinvertebrate communities, were evaluated in 12 stream sites within the Xitiaoxi River watershed, China, from April 2009 to January 2010. The composition of macroinvertebrate community differed significantly among three land use types. Forested sites were characterized by high taxa richness, diversity and the benthic‐index of biotic integrity (B‐IBI), while farmland and urban disturbed stream sites presented contrary patterns. The percentage of urban land use, conductivity, dissolved oxygen, ammonia nitrogen and total phosphorus were the major drivers for the variations. The land use related water quality stress gradients of the four sampling seasons were determined by means of four independent Principal Component Analyses. The responses of macroinvertebrate community metrics, to anthropogenic stressors, were explored using Spearman Rank Correlation analyses. All the selected metrics, including total numbers of taxa, numbers of Ephemeroptera, Plecoptera and Trichoptera taxa, percentage of non‐insect abundance, percentage of scrapers abundance, Pielou’s evenness index, Simpson diversity index, and the Benthic Index of Biotic Integrity were correlated significantly with environmental gradients (PC1) in autumn. In other seasons such correlations were less pronounced. Our results imply that autumn is the optimal time to sample macroinvertebrate communities, and to conduct water quality biomonitoring in this subtropical watershed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Glucose‐6‐phosphate metabolism in Plasmodium falciparum
Authors: Preuss Janina , Jortzik Esther , Becker Katja
Published: June 2012

Malaria is still one of the most threatening diseases worldwide. The high drug resistance rates of malarial parasites make its eradication difficult and furthermore necessitate the development of new antimalarial drugs. Plasmodium falciparum is responsible for severe malaria and therefore of special interest with regard to drug development. Plasmodium parasites are highly dependent on glucose and very sensitive to oxidative stress; two observations that drew interest to the pentose phosphate pathway (PPP) with its key enzyme glucose‐6‐phosphate dehydrogenase (G6PD). A central position of the PPP for malaria parasites is supported by the fact that human G6PD deficiency protects to a certain degree from malaria infections. Plasmodium parasites and the human host possess a complete PPP, both of which seem to be important for the parasites. Interestingly, there are major differences between parasite and human G6PD, making the enzyme of Plasmodium a promising target for antimalarial drug design. This review gives an overview of the current state of research on glucose‐6‐phosphate metabolism in P. falciparum and its impact on malaria infections. Moreover, the unique characteristics of the enzyme G6PD in P. falciparum are discussed, upon which its current status as promising target for drug development is based. © 2012 IUBMB IUBMB Life, 64(7): 603–611, 2012
Lyase activity of glycogen synthase: Is an elimination/addition mechanism a possible reaction pathway for retaining glycosyltransferases?
Authors: Díaz Adelaida , Díaz‐Lobo Mireia , Grados Enrique , Guinovart Joan J. , Fita Ignacio , Ferrer Joan C.
Published: June 2012

Despite the biological relevance of glycosyltrasferases (GTs) and the many efforts devoted to this subject, the catalytic mechanism through which a subclass of this large family of enzymes, namely those that operate with net retention of the anomeric configuration, has not been fully established. Here, we show that in the absence of an acceptor, an archetypal retaining GT such as Pyrococcus abyssi glycogen synthase (PaGS) reacts with its glucosyl donor substrate, uridine 5'‐diphosphoglucose (UDP‐Glc), to produce the scission of the covalent bond between the terminal phosphate oxygen of UDP and the sugar ring. X‐ray diffraction analysis of the PaGS/UDP‐Glc complex shows no electronic density attributable to the UDP moiety, but establishes the presence in the active site of the enzyme of a glucose‐like derivative that lacks the exocyclic oxygen attached to the anomeric carbon. Chemical derivatization followed by gas chromatography/mass spectrometry of the isolated glucose‐like species allowed us to identify the molecule found in the catalytic site of PaGS as 1,5‐anhydro‐D‐arabino‐hex‐1‐enitol (AA) or its tautomeric form, 1,5‐anhydro‐D‐fructose. These findings are consistent with a stepwise SNi‐like mechanism as the modus operandi of retaining GTs, a mechanism that involves the discrete existence of an oxocarbenium intermediate. Even in the absence of a glucosyl acceptor, glycogen synthase (GS) promotes the formation of the cationic intermediate, which, by eliminating the proton of the adjacent C2 carbon atom, yields AA. Alternatively, these observations could be interpreted assuming that AA is a true intermediate in the reaction pathway of GS and that this enzyme operates through an elimination/addition mechanism. © 2012 IUBMB Life, 64(7): 649–658, 2012.
Application of Graphene as a Sorbent for Simultaneous Preconcentration and Determination of Trace Amounts of Cobalt and Nickel in Environmental Water and Vegetable Samples
Authors: Wang Yu‐Kun , Gao Shu‐Tao , Ma Jing‐Jun , Li Jing‐Ci
Published: June 2012

A new method using a column packed with graphene as adsorbent was developed for the preconcentration of trace amounts of cobalt (Co) and nickel (Ni) prior to their determinations by flame atomic absorption spectrometry. Several factors influencing the extraction efficiency of Co and Ni and their subsequent determinations, such as pH, amounts of the chelating agent, flow rates of sample and eluent solution, eluent type and its volume, breakthrough volume, and adsorption capacity were established. Under the optimum conditions, the calibration graphs were linear in the range of 4.0‐200.0 μg L−1 and 5.0‐200.0 μg L−1 with detection limits of 0.36 μg L−1 and 0.51 μg L−1 for Co and Ni, respectively. Good relative standard deviations for ten determinations of 100.0 μg L−1 of Co and Ni were 3.2 and 3.6%, respectively. The results for determination of Co and Ni in tap water, river water, sea water, vegetable and spiked samples have demonstrated the accuracy and applicability of the proposed method. To validate the proposed method, three certified reference materials of environment water (GSBZ 50030‐94 and GSB 07‐1186‐2000) and tomato leaf (GSBZ 51001‐94) were analyzed, and the determined values were in good agreement with the certified values.
Germline stem cell lineage tracing by free‐floating immunofluorescent assay of mouse seminiferous tubule
Authors: Jin Bo , Guo Bin , Che Guanyu , Sun Yixue , Liu Yang , Zhang Xueming
Published: June 2012

Whole‐mount immunohistochemistry (whole‐mount IH) of the seminiferous tubule is widely used to investigate the self‐renewal and differentiation of spermatogonial stem cells (SSCs). Examination of the length of spermatogonial cysts is critical for tracing SSCs lineage by using Whole‐mount IH. However, it is difficult for antibody molecules to penetrate into the depth of seminiferous epithelium because its thickness and the tight peritubular myoid and basement membrane outside. Here, we developed a free‐floating immunofluorescent procedure of mouse seminiferous tubules using regular incubation time and normal antibody concentration. Microscopic results showed that undifferentiated spermatogonia were positively labeled by promyelocytic leukemia zinc finger protein, E‐cadherin, and glial cell line‐derived neurotrophic factor family receptor alpha 1, respectively. Spermatogonial cysts in varied length were revealed clearly and spermatogonia subpopulations including Asingle(As), Apaired(Apr), and Aaligned(Aal) were distinguished in lower background images. This method provides us an alternate simple way to trace the lineage of individual SSCs and show their three‐dimensional locations and distributions within their niches anatomically in next step. Microsc. Res. Tech. 75:1150–1153, 2012. © 2012 Wiley Periodicals, Inc.
Effective, safe nonviral gene transfer to preserve the chondrogenic differentiation potential of human mesenchymal stem cells
Authors: Elsler Sebastian , Schetting Sarah , Schmitt Gertrud , Kohn Dieter , Madry Henning , Cucchiarini Magali
Published: June 2012

Background

Genetic modification of mesenchymal stem cells (MSCs) comprises a promising tool to generate cell‐ and gene‐based platforms for regenerative approaches of articular cartilage repair. In the present study, we systematically screened a panel of 15 nonviral compounds for their ability to promote safe, efficient and durable gene expression in human bone marrow‐derived MSCs (hMSCS) without impeding their commitment towards chondrogenic differentiation.

Methods

Primary hMSCs were transfected with plasmid vectors carrying sequences for the Photinus pyralis luciferase Escherichia coli β‐galactosidase, or human insulin‐like growth factor I via 15 nonviral formulations. Transgene expression and transfection efficiencies were monitored for each component in parallel with the effects on cell viability and cytotoxicity. Upon optimization, the most promising reagent was then evaluated for a possible influence on the chondrogenic potential of hMSCs.

Results

Among all formulations tested, GeneJammer® gave the best results for transgene expression and transfection efficacy (25–14% from days 2–21 in monolayer cultures and 35% in 21‐day aggregate cultures), allowing for high levels of viability (92–94%) and modest cytotoxicity (< 12%). Most notably, the application of this reagent did not affect the potential of the cells for chondrogenic differentiation when maintained in long‐term (21 days) three‐dimensional (aggregate) cultures.

Conclusions

The data indicate that safe, efficient transgene expression can be achieved in hMSCs over time using the nonviral GeneJammer® compound, showing promise for future therapeutic settings aiming to treat human articular cartilage disorders. Copyright © 2012 John Wiley & Sons, Ltd.
The spinal cord supports of vertebrae in the crown‐group salamanders (Caudata, Urodela)
Authors: Skutschas Pavel P. , Baleeva Nataly V.
Published: June 2012

The development of spinal cord supports (bony thickenings which extend into the vertebral canal of vertebrae) in primitive (Salamandrella keyserlingii) and derived (Lissotriton vulgaris) salamanders were described. The spinal cord supports develop as the protuberances of periostal bone of the neural arches in the anteroproximal part of the septal collagenous fibers which connect a transverse myoseptum with the notochord and spinal cord, in the septal bundle inside the vertebral canal. Spinal cord supports were also found in some teleostean (Salmo salar, Oncorhynchus mykiss) and dipnoan (Protopterus sp.) fishes. The absence of the spinal cord supports in vertebrates with cartilaginous vertebrae (lampreys, chondrichthyan, and chondrostean fishes) corresponds to the fact that the spinal cord supports are bone structures. The absence of the spinal cord supports in frogs correlates with the lack of the well developed septal bundles inside the vertebral canal. The spinal cord supports are, presumably, a synapomorphic character for salamanders which originated independently of those observed in teleostean and dipnoan fishes. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.
Comparative anatomy of slime glands in onychophora (velvet worms)
Authors: Baer Alexander , Mayer Georg
Published: June 2012

Onychophorans use a unique hunting and defense strategy, which involves the ejection of an adhesive slime secretion produced by a pair of specialized glands. So far, a comparative study on the anatomy of these glands has not been carried out among different species. In this article, we compare anatomical features of slime glands in representatives of two major onychophoran subgroups, the Peripatopsidae and the Peripatidae, from different parts of the world. Our data show that the musculature of the reservoir is conserved whereas the composition of the secretory duct displays taxon‐specific variation. Major differences concern the arrangement of glandular endpieces, which are distributed along the duct in Peripatopsidae but condensed in numerous repeated rosettes in Peripatidae. In addition, there are differences in the attachment pattern of slime glands to the inner surface of the body wall and to the outer surface of the gut between the two major onychophoran subgroups. A tube‐like structure with a putative valve‐like function is found at the transition of the secretory duct and the reservoir in the five Peripatopsidae species studied whereas it is absent in the two representatives of Peripatidae. Our findings suggest that the arrangement of musculature in the reservoir of the slime gland has remained unchanged since the divergence of Peripatidae and Peripatopsidae, while the composition of the secretory duct has been altered in one of these groups. However, the direction of evolutionary changes in duct composition cannot be determined unambiguously due to current uncertainty regarding the phylogenetic relationships of Onychophora. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.
Behavioural modelling of amplifier asymmetry in the time domain
Authors: Jang W. , Kriplani N. M. , Steer M. B.
Published: June 2012

Power amplifier asymmetry is captured by a behavioural model that contains multiple slices representing the amplifier's nonlinearity and long‐term, that is low frequency, memory. The simulation is performed entirely in the time domain, and the expense associated with performing a purely transient radio frequency (RF) simulation is circumvented by scaling down the carrier frequency by two orders of magnitude. This leads to a manageable transient simulation with results scaling back to the original carrier frequency. The model is empirical and can be easily implemented in any general purpose circuit simulation environment. The baseband portion of the model parameters was extracted and the simulation result was compared with measurement, thereby demonstrating that a nonlinear and accurate transient analysis routine can be effectively employed to capture memory‐related RF power amplifier phenomena. Copyright © 2012 John Wiley & Sons, Ltd.
GPU‐based acceleration of computational electromagnetics codes
Authors: Donno Danilo De , Esposito Alessandra , Monti Giuseppina , Catarinucci Luca , Tarricone Luciano
Published: June 2012

The solution of large and complex electromagnetic (EM) problems often leads to a substantial demand for high‐performance computing resources and strategies. This is true for a wide variety of numerical methods and applications, ranging from EM compatibility to radio‐coverage, circuit modeling, and optimization of components. In the last decades, graphics processing units (GPUs) have gained popularity in scientific computing as a low‐cost and powerful parallel architecture. This paper gives an overview of the main efforts of researchers to port computational electromagnetics (CEM) codes to GPU. Moreover, GPU implementation aspects of two well‐known techniques, namely the finite‐difference time domain (FDTD) and the method of moments (MoM), are investigated. The impressive speed‐ups achieved (up to 60× and 25× for FDTD and MoM, respectively) demonstrate the effectiveness of GPUs in accelerating CEM codes. Copyright © 2012 John Wiley & Sons, Ltd.
Bioactivity and Viscoelastic Characterization of Chitosan/Bioglass® Composite Membranes
Authors: Caridade Sofia G. , Merino Esther G. , Alves Natália M. , Mano João F.
Published: June 2012

Membranes of chitosan (CTS) and composite membranes of CTS with bioglass are prepared by solvent casting. The composite membranes are shown to induce the precipitation of apatite upon immersion in SBF. The biomineralization process is followed by measuring the variation of the viscoelastic properties of the membranes immersed in SBF, both online and offline. Non‐conventional DMA is used to measure the change in the storage modulus, E′, and the loss factor, tan δ, as a function of the immersion in SBF. A simple model is used to estimate the E′ of the apatite layer formed in vitro that is about 130 MPa. This work shows that innovate mechanical tests can be useful to characterize the mechanical performance of composites under physiological conditions.

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Modification of Polydimethylsiloxane Coatings by H2 RF Plasma, Xe2* Excimer VUV Radiation, and Low‐Energy Electron Beams
Authors: Swiderek Petra , Jolondz Evgeni , Bredehöft Jan Hendrik , Borrmann Tobias , Dölle Christopher , Ott Matthias , Schmüser Christoph , Hartwig Andreas , Danilov Vladimir , Wagner Hans‐Erich , Meichsner Jürgen
Published: June 2012

The crosslinking of thin liquid PDMS layers by three different technically relevant processes, H2 radio‐frequency plasma treatment, Xe2* excimer VUV irradiation, and low‐energy electron beam processing is investigated. The modifications to the layers due to the processing are monitored by means of RAIRS. Plasma processing of liquid PDMS leads to a direct conversion to a SiOx‐like material of the topmost layers, whereas a gradual transition from PDMS to the same product is observed upon VUV irradiation. Electron exposure does not induce oxidation. The initiating steps of the conversion induced by the interaction with VUV photons, low‐energy electrons, or their combined effect with ions and H atoms in the plasma are discussed. The latter creates a high density of damage sites.

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Lycopene inhibits angiogenesis both in vitro and in vivo by inhibiting MMP‐2/uPA system through VEGFR2‐mediated PI3K‐Akt and ERK/p38 signaling pathways
Authors: Chen Man‐Ling , Lin Yu‐Hsiu , Yang Chih‐Min , Hu Miao‐Lin
Published: June 2012

Scope

Limited in vitro data show that lycopene may be anti‐angiogenic but with unclear mechanisms. Here, we employed ex vivo and in vivo assays to substantiate the anti‐angiogenic action of lycopene and determined its molecular mechanisms in human umbilical vein endothelial cells (HUVECs).

Methods and results

The anti‐angiogenic activity of lycopene was confirmed by ex vivo rat aortic ring and in vivo chorioallantoic membrane assays. Furthermore, the in vivo matrigel plug assay in mice demonstrated that lycopene implanted s.c. at the highest dose used (400 μg/plug) completely inhibited the formation of vascular endothelial cells induced by vascular endothelial growth factor (VEGF). As expected, lycopene inhibited tube formation, invasion, and migration in HUVECs, and such actions were accompanied by reduced activities of matrix metalloproteinase‐2, urokinase‐type plasminogen activator, and protein expression of Rac1, and by enhancing protein expression of tissue inhibitors of metalloproteinase‐2 and plasminogen activator inhibitor‐1. Moreover, lycopene attenuated VEGF receptor‐2 (VEGFR2)‐mediated phosphorylation of extracellular signal‐regulated kinase (ERK), p38, and Akt as well as protein expression of PI3K.

Conclusion

Our data demonstrate the anti‐angiogenic effect of lycopene both in vitro and in vivo. The anti‐angiogenic activity of lycopene may involve inhibition of MMP‐2/uPA system through VEGFR2‐mediated PI3K‐Akt and ERK/p38 signaling pathways.
Model organisms in molecular nutrition research
Authors: Rubio‐Aliaga Isabel
Published: June 2012

The complexity of food organism interactions necessitates the use of model organisms to understand physiological and pathological processes. In nutrition research, model organisms were initially used to understand how macro and micronutrients are handled in the organism. Currently, in nutritional systems biology, models of increasing complexity are needed in order to determine the global organisation of a biological system and the interaction with food and food components. Originally driven by genetics, certain model organisms have become most prominent. Model organisms are more accessible systems than human beings and include bacteria, yeast, flies, worms, and mammals such as mice. Here, the origin and the reasons to become the most prominent models are presented. Moreover, their applicability in molecular nutrition research is illustrated with selected examples.
Phytoestrogens genistein and daidzein affect immunity in the nematode Caenorhabditis elegans via alterations of vitellogenin expression
Authors: Fischer Malaika , Regitz Charlotte , Kahl Mareike , Werthebach Michael , Boll Michael , Wenzel Uwe
Published: June 2012

Scope

Phytoestrogens, such as the soy isoflavones genistein and daidzein, are suggested to beneficially affect lipid metabolism in humans and thereby contribute to healthy ageing. New evidences show that phytoestrogens might slow ageing processes also by affecting immune processes.

Methods and results

We tested in the nematode Caenorhabditis elegans the effects of 17β‐estradiol, genistein, and daidzein on resistance versus the nematode pathogen Photorhabdus luminescens with focus on vitellogenins, which are invertebrate estrogen‐responsive genes that encode homologues to ApoB100 with impact on immune functions. Here, we show that the estrogen 17β‐estradiol increases the resistance of C. elegans versus P. luminescens by enhancing vitellogenin‐expression at the mRNA and protein level. Knockdown of single out of five functional vits by RNA‐interference blunted the life‐extending effects under heat‐stress of 17β‐estradiol, demonstrating a lack of redundancy for the vitellogenins. RNAi for nhr‐14, a suggested nuclear hormone receptor for estrogens, displayed no influence on 17β‐estradiol effects. The soy isoflavone genistein reduced vitellogenin‐expression and also resistance versus P. luminescens whereas daidzein increased resistance versus the pathogen in a vitellogenin‐dependent manner.

Conclusion

Our studies show that induction of estrogen‐responsive vitellogenin(s) by the phytoestrogen daidzein potently increases resistance of C. elegans versus pathogenic bacteria and heat whereas genistein acts in an antiestrogenic manner.
Dietary rice bran component γ‐oryzanol inhibits tumor growth in tumor‐bearing mice
Authors: Kim Sung Phil , Kang Mi Young , Nam Seok Hyun , Friedman Mendel
Published: June 2012

Scope

We investigated the effects of rice bran and components on tumor growth in mice.

Methods and results

Mice fed standard diets supplemented with rice bran, γ‐oryzanol, Ricetrienol®, ferulic acid, or phytic acid for 2 weeks were inoculated with CT‐26 colon cancer cells and fed the same diet for two additional weeks. Tumor mass was significantly lower in the γ‐oryzanol and less so in the phytic acid group. Tumor inhibition was associated with the following biomarkers: increases in cytolytic activity of splenic natural killer (NK) cells; partial restoration of nitric oxide production and phagocytosis in peritoneal macrophages increases in released the pro‐inflammatory cytokines tumor necrosis factor‐α, IL‐1β, and IL‐6 from macrophages; and reductions in the number of blood vessels inside the tumor. Pro‐angiogenic biomarkers vascular endothelial growth factor (VEGF), cyclooxygenase‐2 (COX‐2), and 5‐lipoxygenase‐5 (5‐LOX) were also significantly reduced in mRNA and protein expression by tumor genes. ELISA of tumor cells confirmed reduced expression of COX‐2 and 5‐LOX up to 30%. Reduced COX‐2 and 5‐LOX expression downregulated VEGF and inhibited neoangiogenesis inside the tumors.

Conclusion

Induction of NK activity, activation of macrophages, and inhibition of angiogenesis seem to contribute to the inhibitory mechanism of tumor regression by γ‐oryzanol.
Integration of miniaturized balun and low‐noise amplifier for single‐in differential‐out applications
Authors: Yang Chin‐Lung , Chiang Ming‐Jeng , Chiang Yi‐Chyun
Published: June 2012

A low‐noise module comprises a low‐noise amplifier and a new type of passive balun, which consists of two λ/8 broadside‐coupled lines and a short redundant line, is presented. The on‐chip balun is not only low lossy and compact size but also provides good amplitude and phase balances at output ports over a quite wide frequency range. The method of designing the new‐type balun fabricated with CMOS IC technology is proposed. An experimental prototype operated at K‐band was designed and fabricated with a commercial 0.18‐μm CMOS technology to verify the effectiveness of the proposed design method. The measured results show the single‐to‐differential gain is about 9 dB, the amplitude imbalance of the output ports is less than 1.0 dB associated with the phase difference of 181 ± 3° over the frequency range of 20–40 GHz. The area of the prototype including the RF probe pads is about 0.73 × 1.28 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2117–2121, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26987
A planar CPW‐fed patch antenna on thin substrate for broadband operation of ISM‐band applications
Authors: Yoon Cheol , Kim Woo‐Su , Jeong Gye‐Taek , Choi Sun‐Ho , Lee Hwa‐Choon , Park Hyo‐Dal
Published: June 2012

This article presents the design and fabrication of three ISM‐bands coplanar waveguide (CPW)‐fed patch antenna on a thin substrate for applications within 2.400–2.484, 5.150–5.350, and 5.725–5.825 GHz bandwidths. The prototype consists of a thin substrate and a CPW‐fed patch. To obtain sufficient bandwidth with −10 dB return loss, a thin substrate layer is inserted under the ground plate and the radiator. A thin substrate CPW‐fed patch that has three ISM‐bands is used. Important design parameters are the radiator's construction, width, length, the substrate height, and the CPW‐fed gaps. From these optimized parameters, a CPW‐fed patch antenna is fabricated and measured. The measured results of the fabricated antenna are obtained from operating bands at 4.23‐GHz bandwidths with a −10 dB return loss referenced to the center frequency, and the peak gain at 3.82 dBi. The experimental radiation efficiency in both the E‐plane and H‐plane is shown to be a pass band total of 50–82%. It is capable of covering three ISM bands at 2.400–2.484 and 5.150–5.350/5.725–5.825 GHz, which is ideally suitable for short‐range wireless applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2199–2202, 2012; View this article online at wileyonlinelibrary.com.). DOI 10.1002/mop.26994
Novel dual‐mode patch band‐pass filters with slot structures
Authors: La Dong‐sheng , Ma Xue‐lian , Chen Haiyan , Wu Ya‐ping
Published: June 2012

Two novel microstrip band‐pass filters using dual‐mode patch resonators with slot structures are proposed and optimized in this article. By using etched slot defected structures in the circle patch resonator and the regular hexagon patch resonator, the filters have remarkable advantages, such as compact size, high selectivity, and simple structure. The proposed band‐pass filters are simulated, fabricated, and measured. Each of the band‐pass filters has two transmission zeros. The measured results prove to be largely consistent with the simulated results. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2130–2133, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27002