Immune gene variability influences roe deer natal dispersal

Dispersal is a key life‐history trait governing the response of individuals, populations and species to changing environmental conditions. In the context of global change, it is therefore essential to better understand the respective role of condition‐, phenotype‐ and genetic‐dependent drivers of dispersal behaviour. Although the importance of immune function and pathogen infestation in determining patterns of dispersal is increasingly recognised, no study to our knowledge has yet investigated the influence of immune gene variability on dispersal behaviour. Here, we filled this knowledge gap by assessing whether individual heterozygosity at five immune gene loci (one from the Major histocompatibility complex and four from encoding Toll‐like receptors) influences roe deer natal dispersal. We found that dispersal propensity was affected by immune gene diversity, suggesting potential pathogen‐mediated selection through over‐dominance. However, the direction of this effect differed between high and low quality individuals, suggesting that dispersal propensity is driven by two different mechanisms. In support of the condition‐dependent dispersal hypothesis, dispersal propensity increased with increasing body mass and, among high quality individuals only (standardized body mass > 18 kg), with increasing immune gene diversity. However, among poor quality individuals, we observed the opposite pattern such that dispersal propensity was higher for individuals with lower immune gene diversity. We suggest that these poor quality individuals expressed an emergency dispersal tactic in an attempt to escape a heavily infested environment associated with poor fitness prospects. Our results have potentially important consequences in terms of population genetics and demography, as well as host–pathogen evolution.     

Adenosine A2A receptor deficiency attenuates the somnogenic effect of prostaglandin D2

Sleep and Biological Rhythms -     

Transition dynamics and selection of the distinct S-DNA and strand unpeeling modes of double helix overstretching

Recent studies have revealed two distinct pathways for the DNA overstretching transition near 65 pN: 'unpeeling' of one strand from the other, and a transition from B-DNA to an elongated double-stranded 'S-DNA' form. However, basic questions concerning the dynamics of these transitions, relative stability of the two competing overstretched states, and effects of nicks and free DNA ends on overstretching, remain open. In this study we report that: (i) stepwise extension changes caused by sequence-defined barriers occur during the strand-unpeeling transition, whereas rapid, sequence-independent extension fluctuations occur during the B to S transition; (ii) the secondary transition that often occurs following the overstretching transition is strand-unpeeling, during which the extension increases by 0.01-0.02 nm per base pair of S-DNA converted to single-stranded DNA at forces between 75 and 110 pN; (iii) even in the presence of nicks or free ends, S-DNA can be stable under physiological solution conditions; (iv) distribution of small GC-rich islands in a large DNA plays a key role in determining the transition pathways; and (v) in the absence of nicks or free ends, torsion-unconstrained DNA undergoes the overstretching transition via creation of S-DNA. Our study provides a new, high-resolution understanding of the competition between unpeeling and formation of S-DNA.     

甘蓝型油菜秦优10号杂交种纯度鉴定的SSR引物筛选

为了建立一套快速可靠的油菜杂交种纯度的鉴定方法,本文以秦优10号及其亲本、杂种ZZH2为试验材料,对前人开发的2对SSR引物(7号引物, 9号引物)进行了再次筛选.结果显示,7号引物不但能很好地区别出混入杂交种中的亲本,还能将杂交种子的同母异父组合种子从杂交种中分离出来,能够用于鉴别秦优10号杂交种子的真伪;9号引物能区分出杂交种和母本,但不能区分开杂交种和父本.同时,本试验利用人工制成的秦优10号杂交种标准样(纯度为100%)以及7份大田鉴定不同纯度梯度的杂交种子对7号引物鉴定结果的准确性进行了验证,鉴定结果与大田鉴定结果基本一致.本文结果将为鉴定秦优10号杂交种纯度提供更准确的技术资料.     

Immunogenetic heterogeneity in a widespread ungulate: the European roe deer (Capreolus capreolus)

Understanding how immune genetic variation is shaped by selective and neutral processes in wild populations is of prime importance in both evolutionary biology and epidemiology. The European roe deer (Capreolus capreolus) has considerably expanded its distribution range these last decades, notably by colonizing agricultural landscapes. This range shift is likely to have led to bottlenecks and increased roe deer exposure to a new range of pathogens that until recently predominantly infected humans and domestic fauna. We therefore investigated the historical and contemporary forces that have shaped variability in a panel of genes involved in innate and acquired immunity in roe deer, including Mhc‐Drb and genes encoding cytokines or toll‐like receptors (TLRs). Together, our results suggest that genetic drift is the main contemporary evolutionary force shaping immunogenetic variation within populations. However, in contrast to the classical view, we found that some innate immune genes involved in micropathogen recognition (e.g. Tlrs) continue to evolve dynamically in roe deer in response to pathogen‐mediated positive selection. Most studied Tlrs (Tlr2, Tlr4 and Tlr5) had similarly high levels of amino acid diversity in the three studied populations including one recently established in southwestern France that showed a clear signature of genetic bottleneck. Tlr2 implicated in the recognition of Gram‐positive bacteria in domestic ungulates, showed strong evidence of balancing selection. The high immunogenetic variation revealed here implies that roe deer are able to cope with a wide spectrum of pathogens and to respond rapidly to emerging infectious diseases.     

Structure Elucidation of the Metabolites of 2', 3', 5'-Tri-O-Acetyl-N 6-(3-Hydroxyphenyl) Adenosine in Rat Urine by HPLC-DAD,ESI-MS and Off-Line Microprobe NMR

2'', 3'', 5''-tri-O-acetyl-N₆-(3-hydroxyphenyl) adenosine (also known as WS070117) is a new adenosine analog that displays anti-hyperlipidemic activity both in vitro and in vivo experiments as shown in many preliminary studies. Due to its new structure, little is known about the metabolism of WS070117. Hence, the in vivo metabolites of WS070117 in rat urine following oral administration were investigated. Identification of the metabolites was conducted using the combination of high-performance liquid chromatography (HPLC) coupled with diode array detector (DAD), ion trap electrospray ionization-mass spectrometry (ESI-MS), and off-line microprobe nuclear magnetic resonance (NMR) measurements. Seven metabolites were obtained as pure compounds at the sub-milligram to milligram levels. Results of structure elucidation unambiguously revealed that the phase I metabolite, N₆-(3-hydroxyphenyl) adenosine (M8), was a hydrolysate of WS070117 by hydrolysis on the three ester groups. N₆-(3-hydr-oxyphenyl) adenine (M7), also one of the phase I metabolites, was the derivative of M8 by the loss of ribofuranose. In addition to two phase I metabolites, there were five phase II metabolites of WS070117 found in rat urine. 8-hydroxy-N₆-(3-hydroxy-phenyl) adenosine (M6) was the product of M7 by hydrolysis at position 8. The other four were elucidated to be N₆-(3-O-β-D-glucuronyphenyl) adenine (M2), N₈-hydroxy-N₆-(3-O-sulfophenyl) adenine (M3), N₆-(3-O-β-D-glucuronyphenyl) adenosine (M4), and N₆-(3-O- sulfophenyl) adenosine (M5). Phase II metabolic pathways were proven to consist of hydroxylation, glucuronidation and sulfation. This study provides new and valuable information on the metabolism of WS070117, and also demonstrates the HPLC/MS/off-line microprobe NMR approach as a robust means for rapid identification of metabolites.     

Isolation and characterization of <Emphasis Type="Italic">Paenibacillus polymyxa</Emphasis> LY214, a camptothecin-producing endophytic bacterium from <Emphasis Type="Italic">Camptotheca acuminata</Emphasis>

Camptothecin (CPT) is mainly produced and extracted from Camptotheca acuminata and Nothapodytes foetida for pharmaceutical use, i.e., the starting material for chemical conversion to the clinical CPT-type drugs. As the third largest plant anticancer drug, the heavy demand on CPT from global market leads to many research efforts to identify new sources for CPT production. Herein we report the isolation and characterization of a CPT-producing endophytic bacterium Paenibacillus polymyxa LY214 from Camptotheca acuminata. A 10.7 μg l^?1 of CPT was presented in the fermentation broth of P. polymyxa LY214. Its CPT production decreased sharply when the strain of the 2nd generation of P. polymyxa LY214 was cultured and fermented. However, the CPT production remained relatively constant from 2.8 μg l^?1 of the 2nd generation to 0.8 μg l^?1 of the 8th generation of P. polymyxa LY214 under optimized fermentation conditions. A 15- to 30-fold increase of CPT yield was observed when the optimized fermentation conditions, together with the addition of putative biosynthetic precursors of CPT and adsorbent resin XAD16, were applied to ferment the strains of the 7th and 8th generation of P. polymyxa LY214. Bioinformatics analysis of the relative species of P. polymyxa LY214 indicates its potential to produce CPT, which will be helpful to decipher the mysteries of CPT biosynthesis.