Combining conservative and variable markers to infer the evolutionary history of Prunus subgen. Amygdalus s.l. under domestication     

Malou Delplancke  Mariana Yazbek  Nils Arrigo  Anahí Espíndola  Helene Joly  Nadir Alvarez 《Genetic Resources and Crop Evolution》2016,63(2):221-234

The genus Prunus L. is large and economically important. However, phylogenetic relationships within Prunus at low taxonomic level, particularly in the subgenus Amygdalus L. s.l., remain poorly investigated. This paper attempts to document the evolutionary history of Amygdalus s.l. and establishes a temporal framework, by assembling molecular data from conservative and variable molecular markers. The nuclear s6pdh gene in combination with the plastid trnSG spacer are analyzed with bayesian and maximum likelihood methods. Since previous phylogenetic analysis with these markers lacked resolution, we additionally analyzed 13 nuclear SSR loci with the δµ² distance, followed by an unweighted pair group method using arithmetic averages algorithm. Our phylogenetic analysis with both sequence and SSR loci confirms the split between sections Amygdalus and Persica, comprising almonds and peaches, respectively. This result is in agreement with biogeographic data showing that each of the two sections is naturally distributed on each side of the Central Asian Massif chain. Using coalescent based estimations, divergence times between the two sections strongly varied when considering sequence data only or combined with SSR. The sequence-only based estimate (5 million years ago) was congruent with the Central Asian Massif orogeny and subsequent climate change. Given the low level of differentiation within the two sections using both marker types, the utility of combining microsatellites and data sequences to address phylogenetic relationships at low taxonomic level within Amygdalus is discussed. The recent evolutionary histories of almond and peach are discussed in view of the domestication processes that arose in these two phenotypically-diverging gene pools: almonds and peaches were domesticated from the Amygdalus s.s. and Persica sections, respectively. Such economically important crops may serve as good model to study divergent domestication process in close genetic pool.  相似文献   

Heavy metals in tropical Lake Kariba,Zimbabwe     

Håkan Berg  Martina Kiibus  Nils Kautsky 《Water, air, and soil pollution》1995,83(3-4):237-252

Metal mining is carried out in the drainage basin of Lake Kariba, Zimbabwe. In an attempt to assess the distribution of heavy metals in the lake ecosystem, the concentrations of chromium (Cr), cadmium (Cd), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), zinc (Zn), and selenium (Se) were analysed in the following ecosystem components at different locations in the lake; water, sediment, aquatic macrophytes, mussels, and carnivorous and herbivorous fish. Concentrations were generally in the same range as in other temperate and tropical aquatic ecosystems, except for Pb and Cd, which were higher in marcrophytes and fish from the lake. Apart from Cd, there were no signs of biomagnification and the highest levels of metals were found in the macrophytes and sediments. While metal contamination in fish is probably a combination of uptake from the food and an equilibrium with the surrounding water, the levels in macrophytes appear to be determined mainly by uptake from the sediment through the roots.  相似文献   

An Experimental Approach to the Porcine Stress Syndrome     

Goran Johansson  Lennart Jonsson  Nils Lannek  Paul Lindberg 《Acta veterinaria Scandinavica》1973,14(5):764

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Kettle holes reflect the biogeochemical characteristics of their catchment area and the intensity of the element-specific input     

Nitzsche  Kai Nils  Kleeberg  Andreas  Hoffmann  Carsten  Merz  Christoph  Premke  Katrin  Gessler  Arthur  Sommer  Michael  Kayler  Zachary E. 《Journal of Soils and Sediments》2022,22(3):994-1009

Journal of Soils and Sediments - Kettle holes are small inland water bodies known to be dominated by terrigenous material; however, the processes and structures that drive the enrichment and...  相似文献   

Genistein Alters the Release of Oxytocin,Prostaglandins, Cortisol and LH during Insemination in Gilts     

M Norrby  N Lundeheim  A Madej 《Reproduction in domestic animals》2011,46(2):316-324

Soya products containing phytooestrogens are widely used as feed for pigs. However, limited data are available on the effects of phytooestrogen on the endocrine status of pigs. The aim of this work was to study the impact of the phytooestrogen genistein added to a soya‐free diet on the hormonal pattern in gilts during oestrus and artificial insemination (AI). Ten gilts were fed a soya‐free diet and fitted with jugular vein catheter through vena auricularis. The gilts were randomly divided into two groups (G‐ and C‐group) where the G‐group was given pure genistein, 1 mg/kg body weight (BW) twice daily, per os. Blood samples were collected before, during and after AI. Oxytocin, prostaglandin E_2, prostaglandin F_2α, 13,14‐dihydro‐15‐keto‐prostaglandin F_2α (PGFM), cortisol and LH concentrations in blood plasma were analysed. Oxytocin concentrations were almost twice as high in the G‐group as in C‐group after the AI. Prostaglandin E₂ concentrations were higher in G‐group than in C‐group during the entire sampling period. After AI, the concentrations of prostaglandin E₂ increased in G‐group but not in C‐group. Prostaglandin F_2α concentration had a pulsatile pattern, with increasing pulses after AI in G‐group. Plasma PGFM concentrations increased after AI with a small variation between the groups. Plasma cortisol concentration increased after AI in C‐group. LH decreased after AI in G‐group. Genistein stimulated elevations of plasma oxytocin and prostaglandin E₂ concentrations and a pulsative pattern in prostaglandin F_2α concentration. The possible involvement of genistein in plasma cortisol and basal LH concentrations in gilts given genistein may also be suggested.  相似文献   

Measuring the CO2 production from maize‐straw‐amended soil columns— a comparison of four methods     

Nils Rottmann  Rainer Georg Joergensen 《植物养料与土壤学杂志》2011,174(3):373-380

A soil‐column experiment with maize‐straw application at different depths was carried out to investigate the accuracy of CO₂‐measurement systems in a greenhouse experiment with sandy and loamy soils. The classical approach of CO₂ absorption in NaOH solution was compared with three other methods using dynamic chambers. These methods were gas chromatography (GC), a portable infrared analyzer (IR), and a portable photo‐acoustic system (PAS). The cumulative CO₂ production over the 57‐day incubation period was significantly affected by the method and soil‐specifically by the treatments. The NaOH and GC method always formed a pair of lowest cumulative CO₂ production in all treatments with maize‐straw addition. In the treatments with bottom application of the maize straw, IR and PAS methods gave values at identical levels in both soils. In the treatments with top application of the maize straw, the IR method gave significantly highest values in the sandy soil and the PAS method in the loamy soil. The correlation coefficients between the cumulative CO₂ production of the three dynamic‐chamber methods (GC, IR, and PAS) and the static NaOH method were all significant, with r values between 0.90 and 0.93. The C balance can be used for testing the plausibility of CO₂‐production data. Roughly 102% (NaOH and GC) and 114% (IR and PAS) were recovered, including the CO₂‐production data in the C balance of the sandy soil. The respective data were 97% (NaOH and GC) and 104% (IR and PAS) for the loamy soil.  相似文献   

Correlating structural dynamics and function in single ribozyme molecules     

Zhuang X  Kim H  Pereira MJ  Babcock HP  Walter NG  Chu S 《Science (New York, N.Y.)》2002,296(5572):1473-1476

We have studied the correlation between structural dynamics and function of the hairpin ribozyme. The enzyme-substrate complex exists in either docked (active) or undocked (inactive) conformations. Using single-molecule fluorescence methods, we found complex structural dynamics with four docked states of distinct stabilities and a strong memory effect where each molecule rarely switches between different docked states. We also found substrate cleavage to be rate-limited by a combination of conformational transitions and reversible chemistry equilibrium. The complex structural dynamics quantitatively explain the heterogeneous cleavage kinetics common to many catalytic RNAs. The intimate coupling of structural dynamics and function is likely a general phenomenon for RNA.  相似文献   

Enols are common intermediates in hydrocarbon oxidation   总被引：1，自引：0，他引：1  

Taatjes CA  Hansen N  McIlroy A  Miller JA  Senosiain JP  Klippenstein SJ  Qi F  Sheng L  Zhang Y  Cool TA  Wang J  Westmoreland PR  Law ME  Kasper T  Kohse-Höinghaus K 《Science (New York, N.Y.)》2005,308(5730):1887-1889

Models for chemical mechanisms of hydrocarbon oxidation rely on spectrometric identification of molecular structures in flames. Carbonyl (keto) compounds are well-established combustion intermediates. However, their less-stable enol tautomers, bearing OH groups adjacent to carbon-carbon double bonds, are not included in standard models. We observed substantial quantities of two-, three-, and four-carbon enols by photoionization mass spectrometry of flames burning representative compounds from modern fuel blends. Concentration profiles demonstrate that enol flame chemistry cannot be accounted for purely by keto-enol tautomerization. Currently accepted hydrocarbon oxidation mechanisms will likely require revision to explain the formation and reactivity of these unexpected compounds.  相似文献   

Electroencephalographic and cardiovascular variables as nociceptive indicators in isoflurane-anaesthetized horses     

Haga HA  Dolvik NI 《Veterinary anaesthesia and analgesia》2005,32(3):128-135

OBJECTIVE: To evaluate Fourier-transformed electroencephalographic (EEG) variables, mean arterial blood pressure (MAP) and pulse rate as nociceptive indicators in isoflurane-anaesthetized horses. ANIMALS: Five standardbred and three Norwegian cold-blooded trotter stallions undergoing castration, aged 2-4 years, mass 378-538 kg. MATERIALS AND METHODS: All horses received intravenous (IV) detomidine (10 microg kg(-1) IV) and butorphanol (0.01 mg kg(-1) IV). Additional detomidine (4 microg kg(-1) IV) was administered in the induction area. Anaesthesia was induced with ketamine (2.5 mg kg(-1) IV) and diazepam (40 microg kg(-1) IV), and maintained for 30 minutes with isoflurane (end-tidal concentration of 1.4%) vaporized in oxygen. The electroencephalogram, MAP and pulse rate were recorded for 15 minutes, beginning 5 minutes before skin incision. Differences between the mean values of recordings taken before, and during surgery were calculated and tested for significant differences using a two-sided Student's t-test. RESULTS: A significant rise in MAP and a fall in pulse rate were found. No significant change was found in any EEG variable. CONCLUSION/CLINICAL relevance Of the variables evaluated, MAP seems to be the most sensitive and reliable indicator of nociception in isoflurane-anaesthetized horses.  相似文献   

Soil CO2 evolution rates in the field – a comparison of three methods     

Evelyn Müller  Nils Rottmann  Anja Bergstermann  Holger Wildhagen 《Archives of Agronomy and Soil Science》2013,59(6):597-608

In this field study, three methods for determining soil CO₂ evolution rates were compared: (1) a static chamber method and (2) a dynamic chamber method, both with gas chromatographic (GC) analysis of air samples, and (3) a dynamic chamber system using a portable infrared gas analyzer (CIRAS). The mean CO₂ evolution rate in the field increased in the order static chamber-GC < dynamic chamber-GC < dynamic chamber-CIRAS by 40%. The CO₂ evolution rates obtained using the three methods were significantly correlated. None of the three methods was significantly affected by soil moisture or soil temperature. This has been repeatedly observed by others, but is still not fully understood. The difference between air and soil temperature had strong negative effects on both GC methods, but not on the CIRAS system.  相似文献