Evolutionarily conserved thermal biology across continents: The North American lizard Plestiodon gilberti (Scincidae) compared to Asian Plestiodon

1.

The lizard genus Plestiodon (Scincidae; formerly Eumeces) is widespread in North America and Asia, but the thermal biology of only a few species has been studied.     

温度对鳙幼鱼疲劳引起的生理变化和游泳能力的影响研究(英文)

鳙(花鲢)在自然环境中分布于中国南部流域至阿穆尔河,是重要的经济性鱼类,具江湖生殖洄游特性。大坝建设阻碍了其洄游产卵繁殖通道,导致自然环境中其繁殖力的下降,需要有效的过鱼设施帮助鳙通过大坝等水流屏障。为了设计高效的鱼道引导鳙通过,本文通过自制密封的鱼类游泳实验装置,研究了鳙幼鱼游泳能力。测定了5个温度(5、10、15、20和25℃)下鳙幼鱼的临界游泳速度。通过测定不同温度下,疲劳前后血清总蛋白(TP)、血糖(GLU)和甘油三酯(TG)含量,评价疲劳运动引起的生理胁迫。结果表明,在试验温度范围内,随着温度的升高,临界游泳速度显著提高(P0.05)。25℃时临界游泳速度最大,为7.01 BL/s(1.19 m/s)。在疲劳运动后,血清总蛋白、血糖和甘油三酯含量显著升高(P0.05)。水温低于15℃与高于15℃相比,鳙疲劳运动后血清总蛋白、血糖和甘油三酯含量显著升高。以鳙幼鱼为研究对象,研究了非适宜温度环境和疲劳运动胁迫下鱼类的生理反应。以期为鱼类生理学研究和渔业保护管理等领域提供理论依据,为制定有效的鱼道提供数据参考。     

切鳍标记对唐鱼游泳能力的影响

本研究通过测定完全切除背鳍、臀鳍、尾鳍或双侧胸鳍后唐鱼（Tanichthys albonubes）临界游泳速度来评价切鳍标记对游泳能力的影响。研究结果表明,在速度增量（ΔU）为36 mm/s,持续时间（Δt）分别为5 min、10 min、15 min、20 min、25 min、30 min的条件下,唐鱼临界游泳速度会随着持续时间的延长而降低。鳍组织完整的唐鱼〔体长（24 ± 1）mm〕,在不同持续时间（Δt）条件下,其绝对临界游泳速度（Uacrit）为（251.98 ± 11.04）mm/s ~（333.78±12.44）mm/s;同等条件下,切除唐鱼的背鳍或臀鳍均不会对唐鱼的绝对临界游泳速度造成显著影响（P＞0.05）,但切除唐鱼的尾鳍或胸鳍后其临界游泳速度与对照组相比极显著降低（P＜0.01）,其中切除尾鳍后绝对临界游泳速度平均下降47.20%,切除胸鳍后平均下降22.98%,两者间存在极显著的差异（P＜0.01）(图2)。研究表明背鳍切除可作为野外唐鱼短期标记-重捕的手段之一。     

Combination stem cell therapy using dental pulp stem cells and human umbilical vein endothelial cells for critical hindlimb ischemia

Narrowing of arteries supplying blood to the limbs provokes critical hindlimb ischemia (CLI). Although CLI results in irreversible sequelae, such as amputation, few therapeutic options induce the formation of new functional blood vessels. Based on the proangiogenic potentials of stem cells, in this study, it was examined whether a combination of dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) could result in enhanced therapeutic effects of stem cells for CLI compared with those of DPSCs or HUVECs alone. The DPSCs+ HUVECs combination therapy resulted in significantly higher blood flow and lower ischemia damage than DPSCs or HUVECs alone. The improved therapeutic effects in the DPSCs+ HUVECs group were accompanied by a significantly higher number of microvessels in the ischemic tissue than in the other groups. In vitro proliferation and tube formation assay showed that VEGF in the conditioned media of DPSCs induced proliferation and vessel-like tube formation of HUVECs. Altogether, our results demonstrated that the combination of DPSCs and HUVECs had significantly better therapeutic effects on CLI via VEGF-mediated crosstalk. This combinational strategy could be used to develop novel clinical protocols for CLI proangiogenic regenerative treatments.     

No trade-off between high and low temperature tolerance in a winter acclimatized Danish Drosophila subobscura population

Coping with cold winter conditions is a major challenge for many insects.In early spring we observed newly emerged Drosophila subobscura, which had overwintered as larvae and pupae. As temperatures increase during spring these flies are faced with higher minimum and maximum temperatures in their natural microhabitat. Thus, there is a potential costly mismatch between winter and early spring acclimatization and the increased ambient temperatures later in adult life.We obtained individuals from a natural Danish population of D. subobscura and acclimated them in the laboratory to 20 °C for one generation, and compared critical thermal maximum (CTmax) and minimum (CTmin) to that of individuals collected directly from their natural microhabitat. The two populations (laboratory and field) were subsequently both held in the laboratory at 20 °C and tested for their CTmax and CTmin every third day for 28 days.At the first day of testing, field acclimatized D. subobscura had both higher heat and cold resistance compared to laboratory flies, and thereby a considerable larger thermal scope. Following transfer to the laboratory, cold and heat resistance of the field flies decreased over time relative to the laboratory flies. Despite the substantial decrease in thermal tolerances the thermal scope remained larger for field acclimatized individuals for the duration of the experiment.We conclude that flies acclimatized to their natural microhabitat had increased cold resistance, without a loss in heat tolerance. Thus while a negative correlation between cold and heat tolerance is typically observed in laboratory studies in Drosophila sp., this was not observed for field acclimatized D. subobscura in this study. We suggest that this is an adaptation to juvenile overwintering in temperate cold environments, where developmental (winter) temperatures can be much lower than temperatures experienced by reproducing adults after emergence (spring). The ability to gain cold tolerance through acclimatization without a parallel loss of heat tolerance affects thermal scope and suggests that high and low thermal tolerance act through mechanisms with different dynamics and reversibility.     

Physical properties of arabinofuranosylcytosine diphosphate diacylglycerol,an antitumor liponucleotide

Dispersed from a dry film into buffer (5 mM phosphate, 0.15 M NaCl, pH 7.4), the liponucleotide 1-β-d-arabinofuranosylcytosine 5′-diphosphate l-1,2-diacylglycerol (ara-CDPdiacylglycerol) spontaneously forms vesicles which are several microns in diameter and probably unilamellar. Their average size immediately begins to decrease, and after 2 h none can be seen in the light microscope. During 1–2 days in unstirred solutions at 25°C, the vesicles are transformed to spherical or nearly spherical micelles having an apparent partial specific volume of 0.835 ml·g^?1, a maximum possible aggregation number of about 150, and an anhydrous radius of about 37 Å. The critical micelle concentration (CMC) is about 10 μM in buffer and 20 μM in distilled water, but micelle-monomer equilibration requires at least 1 week at a total concentration of 66 μM. This exceedingly slow equilibration is unique among reported detergents. The standard enthalpy and entropy of micellization are ?13 kJ·mol^?1 and 87 J·mol^?1·K^?1, respectively. These values are within the range reported for other detergents. Sonication accelerates the vesicle-micelle transformation to 30 min.     

Molecular Dynamics Study of BaB2O4 in Crystalline and Molten States

Abstract

Structural aspects of BaB₂O₄ liquids have been investigated by the molecular dynamics simulation including the determination on the parameters of the interatomic potential applicable to BaB₂O₄ in both crystalline and molten states. The structure and physical properties of BaB₂O₄ crystals were successfully reproduced by the MD simulation for both α and β phases. The simulated interference function in the liquid state was also in good agreement with the experimental one. Several interesting features on the relaxation phenomena just after melting were reproduced by the simulation that the structure factors of simulated liquid maintain the characteristic features of the original crystal structure for more than 40ps after melting, and the variation of the number of rings formed by B-O bondings was found to increase after melting.     

Affinity precipitation an option for early capture in bioprocessing

Affinity precipitation is a bioseparation technique where the affinity ligand is coupled to a stimuliresponsive polymer. Stimuli-responsive polymers show abrupt, yet reversible, phase transition (precipitation) in response to a small change in an environmental parameter. The corresponding ligand conjugates can be used to co-precipitate and thereby capture and isolate target molecules from complex solutions such as culture supernatants and cell lysates. The approach is compatible with a 'discardibles only' type of downstream process and can be scaled over several orders of magnitude. This report discusses the set-up and development of affinity precipitation procedures, the related instrumentation and scale up, as well as applications for the isolation of proteins and polynucleotides.     

Observational study to assess the relationship between enteral nutrition delivery and nutritional biomarkers among mechanically ventilated critically ill patients

BackgroundBiochemical assessment is considered a useful tool in assessing the patient’s nutritional status and intake. However, during critical illness, nutritional biomarkers, such as albumin, and haemoglobin (HB) may reflect the severity of acute illness. The aim of this study is to assess the relationship between energy and protein delivery with the change in albumin, HB, “mean corpuscular volume”(MCV), and “mean corpuscular haemoglobin concentration” (MCHC) levels in critically ill patients.MethodIn this prospective observational study we monitored the intake of energy and protein in a group critically ill patients for 6 consecutive days. Biochemical data including albumin, HB, MCV and MCHC was measured on admission and on day 6 of the follow-up. The variation in the biomarkers between admission and day 6 was calculated as the follow-up reading minus the reading obtained upon admission to (Intensive Care Unit) ICU.ResultsThis study included 43 patients. There was a significant difference in the albumin and HB levels between admission and follow up readings. No statistical association was recorded between the intake and the changes in albumin, MCV and MCHC level during ICU stay. The results showed a significant association between the intake of energy (R = 0.393), and protein (R = 0.385), with the increase in HB level during hospitalisation.ConclusionOverall, this study showed that most nutritional biomarkers were not influenced by nutritional therapy during the acute phase of illness. These findings may directly undermine the usefulness of the serial measurements of these biomarkers in the early phase of ICU admission.