Neospora caninum:Tachyzoites Express a Potent Type-I Nucleoside Triphosphate Hydrolase,but Lack Nucleoside Diphosphate Hydrolase Activity

Asai, T., Howe, D. K., Nakajima, K., Nozaki, T., Takeuchi, T., and Sibley, L. D.Neospora caninum: Tachyzoites Express Type-I Nucleoside Triphosphate Hydrolase1. But Lack Nucleoside Diphosphate Hydrolase Activity.Experimental Parasitology90,277–285. We have identified type I nucleoside triphosphate hydrolase (NTPase; EC 3.6.1.3) activity, previously thought to be restricted to the virulent strains ofToxoplasma gondii, in the cell extracts ofNeospora caninumtachyzoites. Sequence analysis of a complete cDNA from Nc-1 strain indicated thatN. caninumNTPases shared approximately 69% identity to the NTPases ofT. gondiiand are most similar to the NTPase-I isozyme. Southern blot analysis of genomic DNA and sequence analysis of two independentNTPclones from the Nc-1 strain revealed the presence of multiple genes, at least two of which are transcribed. Substrate specificity andK_mvalues for MgATP²⁻and MgADP⁻hydrolysis for recombinant or partially purified native NcNTPase were the same as those for the type I isozyme (NTPase-I). Significantly, no type II enzyme (NTPase-II) activity for NDP hydrolysis was detected in cell extracts ofN. caninum, although it is universally present in allT. gondiistrains that have been tested. This intriguing difference between these two closely related apicomplexan parasites may provide insight into the function of the NTPases during intracellular parasitism.     

Thalidomide‐induced teratogenesis: History and mechanisms

Nearly 60 years ago thalidomide was prescribed to treat morning sickness in pregnant women. What followed was the biggest man‐made medical disaster ever, where over 10,000 children were born with a range of severe and debilitating malformations. Despite this, the drug is now used successfully to treat a range of adult conditions, including multiple myeloma and complications of leprosy. Tragically, a new generation of thalidomide damaged children has been identified in Brazil. Yet, how thalidomide caused its devastating effects in the forming embryo remains unclear. However, studies in the past few years have greatly enhanced our understanding of the molecular mechanisms the drug. This review will look at the history of the drug, and the range and type of damage the drug caused, and outline the mechanisms of action the drug uses including recent molecular advances and new findings. Some of the remaining challenges facing thalidomide biologists are also discussed. Birth Defects Research (Part C) 105:140–156, 2015. © 2015 The Authors Birth Defects Research Part C: Embryo Today: Reviews Published by Wiley Periodicals, Inc.     

Humerus development in moles (Talpidae,Mammalia)

The humerus of fossorial moles has a highly derived anatomy, reflecting the ecological specialization of these animals for digging. It is short and broad, with enlarged muscle attachment sites and pronounced articulations compared to non‐fossorial sister taxa and other mammals. Both condyles are rotated in opposite directions, resulting in a torsion which is unique among eutherian mammals. The development of this exceptional bone was studied in embryonic stages of the fossorial Iberian mole (Talpa occidentalis) from mesenchymal condensation to incipient ossification based on histological serial sections using 3D reconstruction methods. For comparison, embryonic stages of the semi‐fossorial Japanese shrew mole (Urotrichus talpoides) as well as a sister taxon of moles, the terrestrial North American least shrew (Cryptotis parva), were studied. Results show that the humerus of Talpa already shows its derived anatomy with broadened muscle attachment sites and distinct articulations at early cartilaginous stages, when ossification has just started in the mid‐diaphyseal region. The torsion takes place simultaneously with the medial rotation of the forelimbs. The supracondylar foramen is closed in all studied Talpa embryos, but patent in Cryptotis and Urotrichus. This is an example of developmental penetrance, suggesting that variation of adult elements can be found at early stages as well.     

Numerical simulation of the effect of superparamagnetic nanoparticles on microwave rewarming of cryopreserved tissues

In this study, the microwave rewarming process of cryopreserved samples with embedded superparamagnetic (SPM) nanoparticles was numerically simulated. The Finite Element Method (FEM) was used to calculate the coupling of the electromagnetic field and the temperature field in a microwave rewarming system composed of a cylindrical resonant cavity, an antenna source, and a frozen sample phantom with temperature-dependent properties. The heat generated by the sample and the nanoparticles inside the electromagnetic field of the microwave cavity was calculated. The dielectric properties of the biological tissues were approximated using the Debye model, which is applicable at different temperatures. The numerical results showed that, during the rewarming process of the sample phantom without nanoparticles, the rewarming rate was 29.45 °C/min and the maximum temperature gradient in the sample was 3.58 °C/mm. If nanoparticles were embedded in the sample, and the cavity power was unchanged, the rewarming rate was 47.76 °C/min and the maximum temperature gradient in the sample was 1.64 °C/mm. In the presence of SPM nanoparticles, the rewarming rate and the maximum temperature gradient were able to reach 20.73 °C/min and 0.68 °C/mm at the end of the rewarming under the optimized cavity power setting, respectively. The ability to change these temperature behaviors may prevent devitrification and would greatly diminish thermal stress during the rewarming process. The results indicate that the rewarming rate and the uniformity of temperature distribution are increased by nanoparticles. This could be because nanoparticles generated heat in the sample homogeneously and the time-dependent parameters of the sample improved after nanoparticles were homogeneously embedded within it. We were thus able to estimate the positive effect of SPM nanoparticles on microwave rewarming of cryopreserved samples.     

Co-operative Bmp- and Fgf-signaling inputs convert skin wound healing to limb formation in urodele amphibians

Urodele amphibians have remarkable organ regeneration capability, and their limb regeneration capability has been investigated as a representative phenomenon. In the early 19th century, nerves were reported to be an essential tissue for the successful induction of limb regeneration. Nerve substances that function in the induction of limb regeneration responses have long been sought. A new experimental system called the accessory limb model (ALM) has been established to identify the nerve factors. Skin wounding in urodele amphibians results in skin wound healing but never in limb induction. However, nerve deviation to the wounded skin induces limb formation in ALM. Thus, nerves can be considered to have the ability to transform skin wound healing to limb formation. In the present study, co-operative Bmp and Fgf application, instead of nerve deviation, to wounded skin transformed skin wound healing to limb formation in two urodele amphibians, axolotl (Ambystoma mexicanum) and newt (Pleurodeles waltl). Our findings demonstrate that defined factors can induce homeotic transformation in postembryonic bodies of urodele amphibians. The combination of Bmp and Fgf(s) may contribute to the development of novel treatments for organ regeneration.     

Efficient synthesis of the tRNA nucleoside preQ0, 7-cyano-7-deazaguanosine, via microwave-assisted iodo→carbonitrile exchange

The naturally occurring tRNA nucleoside preQ(0), 7-cyano-7-deazaguanosine, which is a central intermediate for other natural occurring 7-deazapurine nucleosides was synthesized via a copper(I)-ion-mediated iodo→carbonitrile exchange. The reaction was performed on the easily accessible 7-iodo-7-deazaguanosine under microwave conditions. The overall reaction yield was 30% starting with the glycosylation reaction of the nucleobase. Corresponding 2'-deoxyribonucleosides were prepared following the same route.     

Extracellular Mg regulates the tight junctional localization of claudin-16 mediated by ERK-dependent phosphorylation

Claudin-16 is involved in the paracellular reabsorption of Mg²⁺ in the thick ascending limb of Henle. Little is known about the mechanism regulating the tight junctional localization of claudin-16. Here, we examined the effect of Mg²⁺ deprivation on the distribution and function of claudin-16 using Madin-Darby canine kidney (MDCK) cells expressing FLAG-tagged claudin-16. Mg²⁺ deprivation inhibited the localization of claudin-16 at tight junctions, but did not affect the localization of other claudins. Re-addition of Mg²⁺ induced the tight junctional localization of claudin-16, which was inhibited by U0126, a MEK inhibitor. Transepithelial permeability to Mg²⁺ was also inhibited by U0126. The phosphorylation of ERK was reduced by Mg²⁺ deprivation, and recovered by re-addition of Mg²⁺. These results suggest that the MEK/ERK-dependent phosphorylation of claudin-16 affects the tight junctional localization and function of claudin-16. Mg²⁺ deprivation decreased the phosphothreonine levels of claudin-16. The phosphothreonine levels of T225A and T233A claudin-16 were decreased in the presence of Mg²⁺ and these mutants were widely distributed in the plasma membrane. Furthermore, TER and transepithelial Mg²⁺ permeability were decreased in the mutants. We suggest that the tight junctional localization of claudin-16 requires a physiological Mg²⁺ concentration and the phosphorylation of threonine residues via a MEK/ERK-dependent pathway.     

2型糖尿病患者血清MCP-1与下肢大血管病变的相关性

目的:讨论2型糖尿病(T2DM)患者血清单核细胞趋化蛋白-1(monocyte chemoattractant protein-1;MCP-1)与下肢大血管病变的相关性。方法:(1)2型糖尿病患者61例,根据是否合并下肢大血管病变,分成无下肢大血管病变组(30例)、合并下肢大血管病变组(31例)与正常对照组(20例)对比,用双抗体夹心ELISA法测出血清MCP-1,比较组间血清MCP-1水平的异常。(2)测出各组甘油三酯、胆固醇、低密度脂蛋白、高密度脂蛋白、空腹血糖、糖化血红蛋白、纤维蛋白原等水平,分析各指标和2型糖尿病大血管病变的相关性。结果:(1)2型糖尿病组血清MCP-1水平明显高于正常对照组(P<0.05),合并下肢大血管病变组血清MCP-1水平明显高于无下肢大血管病变组和正常对照组(P<0.05),(2)以T2DM组为整体,有无下肢大血管病变为因变量Y(有=1,无=0),用MCP-1等其它危险因素为自变量,Logstic回归分析,病程、收缩压和MCP-1入回归方程。结论:MCP-1可能是T2DM下肢大血管病变的一个重要的独立危险因素。