Modeling the estrogen receptor to growth factor receptor signaling switch in human breast cancer cells

Breast cancer cells develop resistance to endocrine therapies by shifting between estrogen receptor (ER)-regulated and growth factor receptor (GFR)-regulated survival signaling pathways. To study this switch, we propose a mathematical model of crosstalk between these pathways. The model explains why MCF7 sub-clones transfected with HER2 or EGFR show three GFR-distribution patterns, and why the bimodal distribution pattern can be reversibly modulated by estrogen. The model illustrates how transient overexpression of ER activates GFR signaling and promotes estrogen-independent growth. Understanding this survival-signaling switch can help in the design of future therapies to overcome resistance in breast cancer.     

Field trapping of male Phyllonorycter ringoniella using variable ratios of pheromone components

The sex pheromone of Phyllonorycter ringoniella (Matsumura) (Lepidoptera: Gracillariidae) has been identified to be a blend of (Z)‐10‐tetradecenyl acetate (Z10‐14:OAc) and E4,Z10‐tetradecadienyl acetate (E4,Z10‐14:OAc) in Japan, Korea, and China. However, the commercial product based on previous results is not attractive enough to be used for monitoring and controlling apple leafminer populations in the field. We re‐investigated the attractiveness of the two pheromone components, singly and in blends, in apple orchards in Shangdong and Shaanxi, the main apple‐growing provinces in China. Our results revealed that Z10‐14:OAc alone was not attractive to P. ringoniella male moths in the field, but E4,Z10‐14:OAc alone not only was strongly attractive but caught more males than any of the blends of Z10‐14:OAc and E4,Z10‐14:OAc tested. The most attractive blend ratios differed slightly for the two locations. No clear dose–response relationship was obtained for the 2:8 blend of Z10‐14:OAc and E4,Z10‐14:OAc. However, the dose–response field study of E4,Z10‐14:OAc alone showed that 1 mg per lure achieved the highest moth catch. These findings differ from the previous report of the best pheromone blend in China. Our data showed that E4,Z10‐14:OAc is the major component of the pheromone of P. ringoniella.     

A spectrophotometric coupled enzyme assay to measure the activity of succinate dehydrogenase

Respiratory complex II (succinate:ubiquinone oxidoreductase) connects the tricarboxylic acid cycle to the electron transport chain in mitochondria and many prokaryotes. Complex II mutations have been linked to neurodegenerative diseases and metabolic defects in cancer. However, there is no convenient stoichiometric assay for the catalytic activity of complex II. Here, we present a simple, quantitative, real-time method to detect the production of fumarate from succinate by complex II that is easy to implement and applicable to the isolated enzyme, membrane preparations, and tissue homogenates. Our assay uses fumarate hydratase to convert fumarate to malate and uses oxaloacetate decarboxylating malic dehydrogenase to convert malate to pyruvate and to convert NADP⁺ to NADPH; the NADPH is detected spectrometrically. Simple protocols for the high-yield production of the two enzymes required are described; oxaloacetate decarboxylating malic dehydrogenase is also suitable for accurate determination of the activity of fumarate hydratase. Unlike existing spectrometric assay methods for complex II that rely on artificial electron acceptors (e.g., 2,6-dichlorophenolindophenol), our coupled assay is specific and stoichiometric (1:1 for succinate oxidation to NADPH formation), so it is suitable for comprehensive analyses of the catalysis and inhibition of succinate dehydrogenase activities in samples with both simple and complex compositions.     

Fused thiazolyl alkynes as potent mGlu5 receptor positive allosteric modulators

A new series of potent fused thiazole mGlu₅ receptor positive allosteric modulators (PAMs) (10, 11 and 27–31) are disclosed and details of the SAR and optimization are described. Optimization of alkynyl thiazole 9 (Lu AF11205) led to the identification of potent fused thiazole analogs 10b, 27a, 28j and 31d. In general, substituted cycloalkyl, aryl and heteroaryl carboxamides, and carbamate analogs are mGlu₅ PAMs, whereas smaller alkyl carboxamide, sulfonamide and sulfamide analogs tend to be mGlu₅ negative allosteric modulators (NAMs).     

Biosynthesis of linoleic acid in Tyrophagus mites (Acarina: Acaridae)

We report here that Tyrophagus similis and Tyrophagus putrescentiae (Astigmata: Acaridae) have the ability to biosynthesize linoleic acid [(9Z, 12Z)-9, 12-octadecadienoic acid] via a Δ12-desaturation step, although animals in general and vertebrates in particular appear to lack this ability. When the mites were fed on dried yeast enriched with d₃₁-hexadecanoic acid (16:0), d₂₇-octadecadienoic acid (18:2), produced from d₃₁-hexadecanoic acid through elongation and desaturation reactions, was identified as a major fatty acid component of phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) in the mites. The double bond position of d₂₇-octadecadienoic acid (18:2) of PCs and PEs was determined to be 9 and 12, respectively by dimethyldisulfide (DMDS) derivatization. Furthermore, the GC/MS retention time of methyl 9, 12-octadecadienoate obtained from mite extracts agreed well with those of authentic linoleic acid methyl ester. It is still unclear whether the mites themselves or symbiotic microorganisms are responsible for inserting a double bond into the Δ12 position of octadecanoic acid. However, we present here the unique metabolism of fatty acids in the mites.     

Midgut aminopeptidase N isoforms from Ostrinia nubilalis: Activity characterization and differential binding to Cry1Ab and Cry1Fa proteins from Bacillus thuringiensis

Aminopeptidase N (APN) isoforms from Lepidoptera are known for their involvement in the mode of action of insecticidal Cry proteins from Bacillus thuringiensis. These enzymes belong to a protein family with at least eight different members that are expressed simultaneously in the midgut of lepidopteran larvae. Here, we focus on the characterization of the APNs from Ostrinia nubilalis (OnAPNs) to identify potential Cry receptors. We expressed OnAPNs in insect cells using a baculovirus system and analyzed their enzymatic activity by probing substrate specificity and inhibitor susceptibility. The interaction with Cry1Ab and Cry1Fa proteins (both found in transgenic insect-resistant maize) was evaluated by ligand blot assays and immunocytochemistry. Ligand blots of brush border membrane proteins showed that both Cry proteins bound mainly to a 150 kDa-band, in which OnAPNs were greatly represented. Binding analysis of Cry proteins to the cell-expressed OnAPNs showed that OnAPN1 interacted with both Cry1Ab and Cry1Fa, whereas OnAPN3a and OnAPN8 only bound to Cry1Fa. Two isoforms, OnAPN2 and OnAPN3b, did not interact with any of these two proteins. This work provides the first evidence of a differential role of OnAPN isoforms in the mode of action of Cry proteins in O. nubilalis.     

Tebufenozide disrupts ovarian development and function in silkmoths

Adult development and production of up to 400 eggs within the pupal case of female silkmoths are both dependent on 20-hydroxyecdysone (20E), the steroid hormone of insects. When adult development was initiated with tebufenozide, the non-steroidal ecdysteroid agonist, instead of 20E, full development of all epidermal tissues like the wing was witnessed, but ovarian growth and egg formation was minimal. Administration of tebufenozide to female pharate adults caused disruption of the follicular epithelium, produced nurse cell damage, and inhibited oogenesis. Reduced ability to synthesize RNA and protein accompanied these tebufenozide induced morphological disturbances of the follicles. In vivo accumulation of vitellogenin (Vg) from the hemolymph was reduced in tebufenozide treated female ovaries as well as their ability to accumulate Vg in vitro. Determination of protein staining intensity and antibody reactivity of Vg pointed out that hemolymph Vg level remained fairly constant all through adult development whether induced by 20E or tebufenozide. Measurement of hemolymph volumes and hemolymph Vg levels of control and experimental animals allowed us to conclude that egg development involves the uptake of all the hemolymph proteins and not Vg alone. The loss of hemolymph that accompanies egg maturation was considerably reduced in tebufenozide initiated female pharate adults. 20E could not overcome ovarian growth inhibitory effects of tebufenozide. Dual mechanisms, one involving ecdysteroid antagonist action at the beginning of development, and the other unrelated to that function during heightened egg formation, are needed explain the biphasic inhibitory actions of tebufenozide on silkmoth ovaries.     

血液净化科室设计中的人因工程因素讨论

?????? 目的 人因工程学是考虑人—机—环境间的关系从而提高工作效率和经济效益的一门学科,希望血液净化科室在设计时引入人因工程学理念,达到改善诊治环境,提高工作效率的目的。 方法 考虑三者需求平衡,通过改造设备、合理布局管道、设计透析单元、引入信息系统等手段达到预期效果。结果 医护和病患对科室环境的满意度较过往高。 结论 考虑人因工程因素可以在科室环境设计中最大程度达到功能和美观的统一。