The Influence of Changes in Magnetic Variations and Light–Dark Cycle on Life-History Traits of Daphnia magna

Day–night cycle is the main zeitgeber (time giver) for biological circadian rhythms. Recently, it was suggested that natural diurnal geomagnetic variation may also be utilized by organisms for the synchronization of these rhythms. In this study, life-history traits in Daphnia magna were evaluated after short-term and multigenerational exposure to 16 h day/8 h night cycle, 32 h day/16 h night cycle, diurnal geomagnetic variation of 24 h, simulated magnetic variation of 48 h, and combinations of these conditions. With short-term exposure, the lighting mode substantially influenced the brood to brood period and the lifespan in daphnids. The brood to brood period, brood size, and body length of crustaceans similarly depended on the lighting mode during the multigenerational exposure. At the same time, an interaction of lighting mode and magnetic variations affected to a lesser extent brood to brood period, brood size, and newborn's body length. The influence of simulated diurnal variation on life-history traits in daphnids appeared distinctly as effects of synchronization between periods of lighting mode and magnetic variations during the multigenerational exposure. Newborn's body length significantly depended on the lighting regime when the periods of both studied zeitgebers were unsynchronized, or on the interaction of light regime with magnetic variations when the periods were synchronized. These results confirm the hypothesis that diurnal geomagnetic variation is an additional zeitgeber for biological circadian rhythms. Possible mechanisms for these observed effects are discussed. Bioelectromagnetics. © 2020 Bioelectromagnetics Society     

海草根际微生物与海草植株的互作效应

【目的】本文以三亚湾泰来草根际沉积物为主要研究对象,研究室内培养条件下泰来草根际沉积物微生物对于高温处理和海草定殖的响应。【方法】通过对培养过程中水体物理化学参数(如pH、溶解氧、磷酸盐、硝酸盐、亚硝酸盐和铵盐)的监测以分析环境因子的变化;16S rRNA扩增子测序研究微生物群落结构的动态响应;通过荧光定量分析16SrRNA基因丰度变化。【结果】研究表明高温处理组在培养35 d后海水中磷酸盐、硝酸盐、亚硝酸盐和铵盐含量以及pH均要高于模拟原位环境的对照组,高温处理组根际沉积物微生物丰度在培养过程中呈现先上升后降低的趋势,同时,高温处理组根际微生物中初始阶段由厚壁菌门(32.4%)、变形菌门(22.92%)和梭杆菌门(27.21%)占据优势,培养一段时间后,厚壁菌门和梭杆菌门大幅度减少,逐渐被蓝细菌门和放线菌门所替代,最终由变形菌门(51.1%)占据主导地位,其中,属于硫还原细菌的脱硫杆菌科(Desulfobacteraceae)和硫氧化细菌的螺杆菌科(Helicobacteraceae)的细菌丰度不断提高。【结论】揭示了海草的定殖会提高高温处理后沉积物的多样性,并塑造和改善其根际沉积物微生物群落组成。     

Day-night variations in pro-oxidant reactions of hypothalamic,hepatic and pancreatic tissue in mice with spontaneous obesity (Neotomodon alstoni)

Objectives: The present work compares the pro-oxidant properties in hypothalamic, hepatic, and pancreatic tissue of spontaneously obese and lean Neotomodon alstoni during day and night. Methods: Lipid peroxidation from hypothalamus, liver, and pancreas from lean and obese mice were quantified by the two-thiobarbituric acid method. Lipid peroxidation in vivo was also determined by means of detection of conjugated dienes in lipid extracts. Results: Hypothalamic tissue from obese Neotomodon showed a notorious increase (nearly 700%) in the production of thiobarbituric acid-reactive substances (TBARS) at day, either in basal as well as in an assay supplemented with Fe²⁺; the presence of conjugated dienes was also notably greater (76%) at day. Hypothalamus of lean mice presented an increase (170%) in assay supplemented with Fe²⁺. Hepatic tissue in obese mice showed diurnal increasing in TBARS + Fe²⁺ (34%) and in conjugated dienes (38%), while lean mice showed only a diurnal increase (45%) in TBARS + Fe²⁺. Pancreatic tissue from obese mice presented a diurnal increasing in basal TBARS (130%) but a decrease (72%) in TBARS + Fe²⁺. Presence of conjugated dienes was also decreased during the day in lean (60%) and in obese (40%) mice. Conclusions: In the obese Neotomodon, there is a larger day–night change in pro-oxidant status in the hypothalamus and in pancreas than the one observed in the liver, suggesting a differential equilibrium between oxidative reactions and antioxidant defenses in the different tissues during the day–night cycle.     

The rate of spontaneous epistaxis is not linked to the lunar cycle but shows seasonal variations

Since 50–60% of the human body consists of water, the physiology of blood circulation might be affected by a full moon differently than during other days of the month. This study analyzed a potential association among lunar phases, seasonal variations, and the rate of spontaneous epistaxis. Consecutive admissions solely for spontaneous epistaxis to an otolaryngology emergency room of a single medical center during 1 year were evaluated. The applied tests failed to show changes of admissions during different lunar phases. According to multiple comparisons, admissions were significantly less frequent during the summer months, similar to findings from other countries of the northern hemisphere with varying climates, suggesting an influence of circannual rhythms rather than of environmental conditions.     

基于水声学方法的天目湖鱼类季节和昼夜空间分布研究

采用水声学方法系统地对天目湖春夏秋冬四季鱼类水平和垂直空间分布进行了调查研究,同时对昼夜探测的差异性进行了比较,并对不同季节间鱼类聚群形态进行了探讨。研究结果表明,天目湖鱼类在不同季节间存在规律性水平迁移,从全湖角度分析,天目湖鱼类资源昼夜间的水平空间分布无明显差异特征,但在春末和夏季的局部区域里,昼夜间鱼类存在一定近岸—远岸的水平迁移;不同季节和昼夜间,鱼类垂直分布差异明显,且在存在温跃层的夏季7月昼间,鱼类密度垂直分布与水温的垂直分布关系密切,温跃层以下的鱼类密度基本为0;天目湖鱼类在四个季节都属于成群分布类型,但季节间鱼类聚群形态不同,在冬季的1月呈现出典型的聚集,相对于昼间,春夏季鱼类在夜间分布更为均匀、分散,且水平探测表明在夜间水体表层存在大量鱼类分布。     

菠萝叶片中有机酸含量、转氨酶和脱氢酶活性的昼夜变化

研究了菠萝叶片中苹果酸、柠檬酸、草酰乙酸、α－酮戊二酸和草酸等有机酸和转氨酶、脱氢酶活性的昼夜变化。结果表明,除了草酸外,其他４种有机酸的含量都呈白天降低晚上增高的趋势。有机酸的含量在上午９∶００时有最高值,下午１８∶００时有最低值。苹果酸、柠檬酸、草酰乙酸、α－酮戊二酸和草酸的昼夜最大差值分别为１４０、６１、３１．８、８．２和６．７ｍｍｏｌ·ｋｇ－１ＦＷ。异柠檬酸脱氢酶和琥珀酸脱氢酶活性的昼夜变化与有机酸的趋势一致,白天降低晚上增高。可溶性蛋白和游离氨基酸含量以及谷草转氨酸、谷丙转氨酶活性在下午１８∶００时有最高值,凝胶电泳显示菠萝叶片中有新的蛋白带出现。     

Is 24-hour energy intake greater during night shift compared to non-night shift patterns? A systematic review

ABSTRACT

Introduction: Epidemiological studies show that shift workers are at increased risk of cardiovascular diseases, metabolic dysfunction, diabetes, and obesity. Previous research has shown no difference in energy intake between night and day shifts only; however, it remains unclear whether other non-night shift patterns are different to night shift.

Objectives: We investigated whether energy intake of night-shift workers differed from other shift patterns using calorimetry, food diary or food recall over 24-hour periods.

Methods: A systematic review was conducted searching CINAHL, MEDLINE, Web of Science, Embase and PsycINFO databases for observational and interventional studies measuring energy intake in real or simulated shift work. Energy intake was extracted to compare night, day, afternoon/evening and rotating shift work cases.

Results: After duplicate removal, we screened 1057 abstracts and 68 full-text articles were assessed for eligibility of which 15 studies met the inclusion criteria. All studies were cross-sectional and case–control designs in shift workers. Risk of bias assessment showed a low to moderate risk of bias in the majority of studies. There was no difference in energy intake between night-shift work and non-night shift patterns including early morning, day and afternoon/evening shifts. Night-shift workers did not favor particular macronutrients in comparison to other shift schedules.

Conclusions: Energy and macronutrient intake were not detectably different in night shift compared to other shift patterns. Shift work patterns were heterogeneous which likely impacted on dietary assessment timings and computation of 24-h energy intake. Future studies should examine shift schedules with precise circadian timing of food consumption to determine if differences exist in energy and macronutrient intake between different shift patterns.     

昼夜温差对番茄生长发育、产量及果实品质的影响

在3间人工气候室精密受控环境中,保持日平均温度为22 ℃,设置昼夜温差分别为6 ℃(25 ℃/19 ℃)、8 ℃(26 ℃/18 ℃)、10 ℃(27 ℃/17 ℃),研究昼夜温差对番茄生长的影响.结果表明: 番茄不同品种、不同生长时期适宜的昼夜温差条件不同.番茄开花前,与6 ℃温差相比,8 ℃温差可显著加快野生种醋栗番茄LA1781生长发育,使幼苗株高增加23.1%,出叶加快1～2片,开花提前7 d;10 ℃温差对LA1781苗期的促进作用与8 ℃温差相似.对栽培种普通番茄LA2397和LA0490来说,6 ℃温差使幼苗生长良好,8 ℃温差对幼苗无显著促进作用;与6 ℃温差相比,10 ℃温差对苗期生长及开花有抑制作用,使株高降低12.0%～18.3%,出叶慢2～3片,开花推迟2～4 d.10 ℃温差使3个品种番茄地上部分干质量增加25.2%～44.2%.番茄开花后,与6 ℃温差相比,10 ℃温差可显著提高LA1781的产量和果实品质,使果实数增加34.7%,单株产量增加92.1%,平均单果质量增加40.0%,果实可溶性糖含量增加16.3%,番茄红素含量增加95.6%.与6 ℃温差相比,LA2397和LA0490在8 ℃温差下产量和果实品质提高,番茄红素含量增加超过2倍;在10 ℃温差下产量略有降低(5.0%),果实含糖量降低,但果实尺寸和番茄红素含量增加.表明番茄苗期生长温差不宜过大,花果期适当增大昼夜温差可提高产量和果实品质,但温差过大易造成生长不良和减产.     

1961-2009年淮河流域昼夜降水变化特征

利用淮河流域162个台站1961-2009年逐时降水资料,采用线性倾向估计、REOF分析、功率谱、Mann-Kendall突变检验等方法,分析淮河流域昼夜降水基本特征及其时空演变规律.结果表明:淮河流域昼夜降水空间差异明显,总体呈北少南多分布,年夜雨量和夜雨日略多于昼雨量和昼雨日,且不同季节和不同强度等级降水昼夜差异显著;气候变化导致淮河流域昼夜降水量格局发生改变,年夜雨量大部地区有增多趋势,年昼雨量呈东部减少而西部增多的趋势.REOF分析表明,年昼夜降水量空间模态基本划分为流域东北部、中北部、西北部、东部、西部和南部等6个高载场区;流域年昼夜降水量均存在7～9a显著主周期振荡,此外年昼雨量还存在2 a左右次周期变化.Mann-Kendall分析表明,年昼夜降水量均分别经历了一次减少和一次增多的突变,但未通过0.05的信度检验.     

VALPROIC ACID HAS TEMPORAL VARIABILITY IN URINARY CLEARANCE OF METABOLITES

The reasons for the intra- and interindividual variability in the clearance of valproic acid (VPA) have not been completely characterized. The aim of this study was to examine day–night changes in the clearance of 3-oxo-valproate (3-oxo-VPA), 4-hydroxy-valproate (4-OH-VPA), and valproic acid glucuronides under steady state. Six diurnally active healthy male volunteers ingested 200 mg sodium valproate 12 hourly, at 0800 and 2000, for 28 days. On the last study day, two sequential 12-h urine samples were collected commencing at 2000 the evening before. Plasma samples were obtained at the end of each collection. Following alkaline hydrolysis, urine was analyzed for concentrations of VPA, 3-oxo-VPA, and 4-OH-VPA. A separate aliquot was assayed for creatinine (CR). The plasma concentrations of VPA, 3-oxo-VPA, 2-en-VPA, and CR were determined. The analysis of VPA and its metabolites was performed by GC–MS. There was an increase in plasma 3-oxo-VPA concentration at 0800, sampling as compared to 2000 sampling (p <. 05). The urinary excretion of 3-oxo-VPA and VPA glucuronides were decreased between 2000 and 0800, compared to between 0800, and 2000, by 40% and 50% respectively (p <. 05). These results indicate a nocturnal decrease in renal clearance of 3-oxo-VPA rather than a decrease in the β-oxidation of VPA at night. These differences were not explained by differences between the sampling periods in CR excretion. These results indicate the importance of collecting samples of 24-h duration when studying metabolic profiles of VPA. (Chronobiology International, 18(1), 123–129, 2001)     

Modelling of temperature-controlled internode elongation applied to chrysanthemum

The DIF concept states that equal internode length can be achieved with the same difference between day and night temperature irrespective of the mean 24 h temperature. However, the physiological background of the DIF concept is unclear. An attempt to model internode elongation is presented based on three plausible processes, namely (1) the accumulation of elongation requirements during the day, (2) elongation during the night using elongation requirements and (3) the limitation of internode length due to low turgor pressure unable to counter cell wall elasticity. Each reaction rate constant, one per process, depends on temperature according to Arrhenius' Law. The resulting process-based model describes internode elongation in time and was calibrated on a chrysanthemum data set. Chrysanthemum plants were grown in growth chambers with rigorously defined day and night temperatures. In total, 16 temperature treatments were applied, resulting from the combination of four day and four night temperatures (16, 20, 24 and 28 degrees C). Internode elongation was measured for the tenth internode in ten plants per treatment. The percentage variance accounted for, R2adj, was almost 91%. Transferability of model parameters was shown to exist by cross validation. Simulation of the internode length in time as function of mean 24 h temperature and DIF showed that the DIF concept is not apparent after a growing period of 10 d, but is visible after 20 d. This model structure for describing internode elongation might also be applicable for other plants that show the DIF concept.     

Postsynthetic Conjugation of RNA to Carboxylate and Dicarboxylate Molecules

Carboxylates and dicarboxylates are important phosphate mimics. Herein, we present a simple synthetic route for the preparation of RNA carboxylate/dicarboxylate conjugates, starting from suitably protected NH₂- and COOH-containing molecules that are coupled to the RNA on the solid support. The key point in our method was the use of trimethylsilylethanol (TMSE-OH) protecting group, which is removed simultaneously with the silyl protecting group on the 2′-OH of the RNA ribose (e.g. t-Butyldimethylsilyl) during the final RNA cleavage/deprotection steps. The usefulness of this method was demonstrated by preparing different RNA-phosphate mimics oligos.