Production of phenolics and the emission of volatile organic compounds by perennial ryegrass (Lolium perenne L.)/Neotyphodium lolii association as a response to infection by Fusarium poae

Grasses very often form symbiotic associations with Neotyphodium/Epichloë endophytic fungi. These endophytes often allow the host grass to be protected from different pathogens. However, there is little known about the mechanisms of such endophyte influence on the host. Thus, the purpose of this research was to examine the effect of the N. lolii endophyte on the total production of phenolic compounds, VOCs emission and the resistance of three perennial ryegrass genotypes infected by pathogenic Fusarium poae. Analyses of total phenolics content were performed in control (not inoculated) and inoculated plants after 1, 2, 3, 4, 5, and 6 days (DAI) and for VOCs after 0, 3, 6 and 12 DAI. The presence of endophytes significantly reduced the disease index in two of the three genotypes relative to that in E−. Plants infected by N. lolii exhibited higher production of phenolics relative to the E− plants. The highest amounts of phenolics were observed on the second and sixth DAI. Genotype Nl22 showed the strongest effect of the endophyte on the production of phenolics, which increased by over 61%. Both the endophyte infected and non-infected plants emitted most abundantly two GLVs ((Z)-3-hexenal, (Z)-3-hexen-1-yl acetate), three terpenes (linalool, (Z)-ocimene, β-caryophyllene) and three shikimic acid pathway derivatives (benzyl acetate, indole, and methyl salicylate). The endophyte presence and the intervals of VOCs detection were a highly significant source of variation for all emitted volatiles (P < 0.001). The genotype of the perennial ryegrass significantly affected only the emission of methyl salicylate (P < 0.05) and β-caryophyllene (P < 0.05). Most of the VOCs ((Z)-3-hexen-1-yl acetate, (Z)-3-hexenal, linalool and methyl salicylate) reached their highest levels of emission on the sixth DAI, when averaged over genotypes and endophyte status. The results highlight the role of Neotyphodium spp. in the mediation of quadro-trophic interactions among plants, symbiotic endophytes, invertebrate herbivores and plant pathogenic fungi. Our results also confirm the fact that symbiotic plants can activate a defense reaction faster than non-symbiotic plants after a pathogen attack. Thus, N. lolii can be involved in the defense of perennial ryegrass against pathogens and potentially could be central to the host plants’ protection.     

Field trapping of male Phyllonorycter ringoniella using variable ratios of pheromone components

The sex pheromone of Phyllonorycter ringoniella (Matsumura) (Lepidoptera: Gracillariidae) has been identified to be a blend of (Z)‐10‐tetradecenyl acetate (Z10‐14:OAc) and E4,Z10‐tetradecadienyl acetate (E4,Z10‐14:OAc) in Japan, Korea, and China. However, the commercial product based on previous results is not attractive enough to be used for monitoring and controlling apple leafminer populations in the field. We re‐investigated the attractiveness of the two pheromone components, singly and in blends, in apple orchards in Shangdong and Shaanxi, the main apple‐growing provinces in China. Our results revealed that Z10‐14:OAc alone was not attractive to P. ringoniella male moths in the field, but E4,Z10‐14:OAc alone not only was strongly attractive but caught more males than any of the blends of Z10‐14:OAc and E4,Z10‐14:OAc tested. The most attractive blend ratios differed slightly for the two locations. No clear dose–response relationship was obtained for the 2:8 blend of Z10‐14:OAc and E4,Z10‐14:OAc. However, the dose–response field study of E4,Z10‐14:OAc alone showed that 1 mg per lure achieved the highest moth catch. These findings differ from the previous report of the best pheromone blend in China. Our data showed that E4,Z10‐14:OAc is the major component of the pheromone of P. ringoniella.     

Synthesis of (3E, 5Z)-3,5-Dodecadienylacetate,the Sex Pheromone of Phtheochroa cranaodes (Lepidoptera: Tortricidae)

(3E, 5Z)-3,5-Dodecadienyl acetate, the female sex pheromone of Phtheochroa cranaodes, was regio and stereo-selectively synthesized from 1-octyne and (E)-4-bromo-3-buten-1-ol by using Pd(PPh₃)₄, CuI and piperidine to afford the enyne (5). Further elaboration afforded the target pheromone. The synthetic pheromone was identified with the natural product by its MS and IR, data GLC retention time and biological activity.     

Production and Characterization of a Pressure-induced Gel from Freeze-concentrated Milk

A process was developed to produce a characteristic milk gel. Raw and market milk samples were freeze-concentrated using bacterial ice nuclei. The concentrates were kept at 5°C and compressed at 300–600 MPa for 5 min. The combination of the freeze concentration and the pressurization gave a milk gel without adding any gelling agents. The addition of sugar at 10% to the concentrated milk improved its gel strength and viscoelasticity. The gel was characterized by a phase transition at about 62–75°C.     

植物叶绿体分裂的分子机制

叶绿体是植物细胞内一种重要的细胞器．它不仅是光合作用的场所,还是其它多种中间代谢的场所．叶绿体起源于蓝细菌,与其原核祖先类似,通过二分裂方式进行增殖．最近的研究表明,叶绿体的分裂装置包含原核起源和真核起源的蛋白质,它们在叶绿体的内膜内侧和外膜外侧协同作用以完成叶绿体的分裂．在过去十几年里,包括丝状温度敏感蛋白Z（FtsZ）、Min系统蛋白、质体分裂蛋白（PDV）和ARC蛋白等在内的多个叶绿体分裂相关组分被分离鉴定．本文简要介绍了叶绿体分裂装置各成员的发现、叶绿体被膜的收缩和叶绿体分裂位点的选择机制．另外,植物发育过程中叶绿体分裂可能受到细胞的控制,但目前对细胞如何调控叶绿体分裂知之甚少．本文对该领域的最新研究进展也进行了综述．     

香梨优斑螟性信息素化学合成及雄蛾数量动态监测

香梨优斑螟是一种严重危害库尔勒香梨的重要害虫之一,利用昆虫性信息素防控和监测香梨优斑螟,可为香梨生产提供科学的绿色防控依据。本文通过化学合成方法得到香梨优斑螟性信息素活性组分:顺,反-9,12-十四碳二烯-1-醇(Z9E12-14∶OH),并利用标准化合物研究了香梨优斑螟雄蛾的野外发生规律。结果表明:香梨优斑螟性信息素活性组分对雄蛾有较好的引诱活性,诱蛾高峰十分明显,此虫在阿克苏地区包括越冬代在内一年发生3代,分别是4月中下旬、6月上中旬和7月中下旬。因此,该性引诱剂可为香梨优斑螟的综合防控提供技术支持。     

Biochemical characterization of the placeholder nucleosome for DNA hypomethylation maintenance

DNA methylation functions as a prominent epigenetic mark, and its patterns are transmitted to the genomes of offspring. The nucleosome containing the histone H2A.Z variant and histone H3K4 mono-methylation acts as a “placeholder” nucleosome for DNA hypomethylation maintenance in zebrafish embryonic cells. However, the mechanism by which DNA methylation is deterred by the placeholder nucleosome is poorly understood. In the present study, we reconstituted the placeholder nucleosome containing histones H2A.Z and H3 with the Lys4 mono-methylation. The thermal stability assay revealed that the placeholder nucleosome is less stable than the canonical nucleosome. Nuclease susceptibility assays suggested that the nucleosomal DNA ends of the placeholder nucleosome are more accessible than those of the canonical nucleosome. These characteristics of the placeholder nucleosome are quite similar to those of the H2A.Z nucleosome without H3K4 methylation. Importantly, the linker histone H1, which is reportedly involved in the recruitment of DNA methyltransferases, efficiently binds to all of the placeholder, H2A.Z, and canonical nucleosomes. Therefore, the characteristics of the H2A.Z nucleosome are conserved in the placeholder nucleosome without synergistic effects on the H3K4 mono-methylation.     

Vibrational and electronic circular dichroism study of the interactions of cationic porphyrins with (dG-dC)10 and (dA-dT)10

The interactions of two different porphyrins, without axial ligands-5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin-Cu(II) tetrachloride (Cu(II)TMPyP) and with bulky meso substituents-5,10,15,20-tetrakis(N,N,N-trimethylanilinium-4-yl)porphyrin tetrachloride (TMAP), with (dG-dC)10 and (dA-dT)10 were studied by combination of vibrational circular dichroism (VCD) and electronic circular dichroism (ECD) spectroscopy at different [oligonucleotide]/[porphyrin] ratios, where [oligonucleotide] and [porphyrin] are the concentrations of oligonucleotide per base-pair and porphyrin, respectively. The combination of VCD and ECD spectroscopy enables us to identify the types of interactions, and to specify the sites of interactions: The intercalative binding mode of Cu(II)TMPyP with (dG-dC)(10), which has been well described, was characterized by a new VCD "marker" and it was shown that the interaction of Cu(II)TMPyP with (dA-dT)10 via external binding to the phosphate backbone and major groove binding caused transition from the B to the non-B conformer. TMAP interacted with the major groove of (dG-dC)10, was semi-intercalated into (dA-dT)10, and caused significant variation in the structure of both oligonucleotides at the higher concentration of porphyrin. The spectroscopic techniques used in this study revealed that porphyrin binding with AT sequences caused substantial variation of the DNA structure. It was shown that VCD spectroscopy is an effective tool for the conformational studies of nucleic acid-porphyrin complexes in solution.     

Precise bacterial polyprenol length control fails in Saccharomyces cerevisiae

A comparison of amino acid sequences of yeast Rer2p and Srt1p Z-prenyltransferases shows that the spatial organization of their substrate tunnels agrees with that determined by X-ray for the E. coli undecaprenyl diphosphate synthase (UPPs). The observed trend in the maxima of product length distribution shifted from C(55) in UPPs to C(80) in Rer2p and to C(110) in Srt1p. This suggests a significant increase in the size of the enzyme hydrophobic tunnel from approximately 1000 A(3) of E. coli UPPs to approximately 1300 A(3) required to accommodate C(80) in Rer2p and to 1700 A(3) for C(110) in Srt1p. Moreover, Srt1p products reaching C(290) indicate the failure of a strict bacterial-like chain length control. On the basis of E. coli UPPs crystallographic structure the yeast Rer2p model was constructed. In the model three amino acid residues inserted into the sequence corresponding to the "floor" region of the tunnel extends the bottom loop what results in the required increase of the tunnel volume. Moreover, thermal fluctuations of this loop occasionally create a hole in the tunnel floor, making escape of polyprenol omega end out of the tunnel possible what switches off the control mechanism of product length thereby allowing a practically unlimited elongation process leading to an exponential distribution of longer chain polyprenols.     

Isolation and characterization of sex chromosome rearrangements generating male muscle dystrophy and female abnormal oogenesis in the silkworm, Bombyx mori

In deletion-mapping of W-specific RAPD (W-RAPD) markers and putative female determinant gene (Fem), we used X-ray irradiation to break the translocation-carrying W chromosome (W ^Ze ). We succeeded in obtaining a fragment of the W ^Ze chromosome designated as Ze ^W, having 3 of 12 W-RAPD markers (W-Bonsai, W-Yukemuri-S, W-Yukemuri-L). Inheritance of the Ze ^W fragment by males indicates that it does not include the Fem gene. On the basis of these results, we determined the relative positions of W-Yukemuri-S and W-Yukemuri-L, and we narrowed down the region where Fem gene is located. In addition to the Ze ^W fragment, the Z chromosome was also broken into a large fragment (Z₁) having the + ^sch (1-21.5) and a small fragment (Z₂) having the + ^od (1-49.6). Moreover, a new chromosomal fragment (Ze ^WZ₂) was generated by a fusion event between the Ze ^W and the Z₂ fragments. We analyzed the genetic behavior of the Z₁ fragment and the Ze ^WZ₂ fragment during male (Z/Z₁ Ze ^WZ₂) and female (Z₁ Ze ^WZ₂/W) meiosis using phenotypic markers. It was observed that the Z₁ fragment and the Z or the W chromosomes separate without fail. On the other hand, non-disjunction between the Ze ^WZ₂ fragment and the Z chromosome and also between the Ze ^WZ₂ fragment and the W chromosome occurred. Furthermore, the females (2A: Z/Ze ^WZ₂/W) and males (2A: Z/Z₁) resulting from non-disjunction between the Ze ^WZ₂ fragment and the W chromosome had phenotypic defects: namely, females exhibited abnormal oogenesis and males were flapless due to abnormal indirect flight muscle structure. These results suggest that Z₂ region of the Z chromosome contains dose-sensitive gene(s), which are involved in oogenesis and indirect flight muscle development.