大黄酚和大黄素甲醚的制备性分离

经系统分离得到大黄酚和大黄素甲醚的混合物后,取该混合物约1g,用少量的氯仿溶解,加入少量的层析用硅胶（100～200目）拌匀,减压使氯仿蒸干。将吸附有大黄酚和大黄素甲醚的硅胶装在已装好的硅胶层析柱的上端,然后进行洗脱。通过实验,得到了最佳分离大黄酚和大黄素甲醚的条件：硅胶与混合物的质量比=150：1;层析柱长与直径的比=23：1;洗脱剂比例：石油醚（60～90℃）：乙酸乙酯（V/V）=17：1;减压淋洗。     

Physcion-8-O-gentiobioside from Rhamnus virgata

A new anthraquinone diglucoside isolated from Rhamnus virgata has been shown to be physcion-8-O-β-gentiobioside on the basis of spectral and other evidence.     

Anthraquinones from Vismia species

1,8-Dihydroxy-3-methyl-6-methoxyanthraquinone (physcion) and two derivatives, 7-(trans-3-methyl-1-butenyl)-physcion (vismiaquinone) and 7-(3-methyl-2-oxobutyl)-physcion (vismiaquinone B), were isolated respectively from Vismia cayennensis and V. japurensis.     

Inhibitory Action of Biofungicide Physcion on Initial and Secondary Infection of Magnaporthe oryzae

Rice blast, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most destructive plant diseases in the world and a serious threat to global food security. Biofungicide physcion, extracted from roots of Chinese traditional herb rhubarb, has been commercialized to control cucumber powdery mildew (Podosphaera fuliginea) in China as a new active and environmentally‐friendly ingredient. This study investigated its bioactivity on rice blast and impact on the infection of M. oryzae. Physcion was effective on M. oryzae with 50% inhibition concentration of 18.19 mg/l on the fungus mycelium growth in vitro and provided 86 and 98% control efficacy in vivo at the concentrations of 40 and 60 mg/l, respectively. It inhibited the initial infection of M. oryzae by inhibiting growth of mycelia, the germination of conidia and the formation of appressoria. Moreover, it inhibited the secondary infection of the fungus at the concentration of 40 mg/l, but had no influence at the low concentrations of 1.25–20 mg/l. So physcion might be a promising natural plant extract that is worthy of being explored to apply on the control of rice blast.     

Effect of the anthraquinones emodin and physcion on availability of selected soil inorganic ions

The effects of emodin and physcion, two anthraquinones involved in Polygonum sachalinense allelopathy, were studied in soils amended with 5, 10 and 15 mg 100 g^-1 soil of each compound, and with their mixtures. Recovery of each compound and its effects on availability of soil Mn⁺⁺, Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺ and PO₄^3- were monitored. Total phenolic content of each soil was determined to study the role of degraded phenolics. Soil amended with 5 mg of emodin and physcion gave maximum recovery of the two anthraquinones. Soil amended with different amounts of two anthraquinones and their mixture had significant lower values for pH compared to control. In general, both anthraquinones affect availability of soil inorganic ions. Compared to unamended control soil, a significant decrease in Mn⁺⁺ availability, and an increase in Na⁺ and K⁺ availability when emodin and physcion were added to the soil was observed. A correlation among soil inorganic ions, relative recovery of two compounds, and total phenolic content of amended soils was observed. Results indicate that emodin and physcion influence the availability of soil inorganic ions. The significance of the effect of allelopathic compounds on soil inorganic ions is discussed.     

Distribution of anthraquinone pigments in Rumex species of Kenya

A correspondence between pigment structures and leaf morphology has been found in Kenyan Rumex species.     

Photosynthates stimulate the UV-B induced fungal anthraquinone synthesis in the foliose lichen Xanthoria parietina

Synthesis of the cortical anthraquinone pigment parietin (= physcion) was studied in acetone‐rinsed, parietin‐free Xanthoria parietina thalli. UV‐B induced the synthesis, which increased linearly with UV‐B (log‐transformed) to the highest applied UV‐B level (1.8 W m^?2). At natural UV‐B levels (0.75 W m^?2), parietin resynthesis occurred at a constant pace (106 mg m^?2 d^?1) during a 14‐d period at 220 µmol m^?2 s^?1 PAR. Under these conditions, 56% of the natural parietin content prior to extraction was resumed, accounting for 10% of total net carbon gain. In the presence of UV‐B, the remaining results were consistent with the hypothesis assuming that photosynthates regulate the pace at which parietin is synthesized by the mycobiont. Resynthesis was rapid when photosynthesis was activated by light, or when certain carbohydrates were added exogenously. Additions of ribitol, the carbohydrate delivered from the photobiont, increased the parietin resynthesis substantially. Mannitol, the main fungal polyol, was significantly less effective. Furthermore, parietin resynthesis in X. parietina was depressed at high and low hydration when net photosynthesis is depressed. Therefore, the photobiont regulates the parietin resynthesis pace in its mycobiont partner by the delivery of photosynthates. In conclusion, both lichen bionts play important roles in the synthesis of parietin, which probably acts as a PAR‐ rather than a UV‐B‐screen.     

Three new triterpenes from the lichen Xanthoria resendei

The three new migrated hopene type triterpenes 12α-acetoxy-3β-hydroxyfern-9(11)-ene, 3β,12α-dihydroxyfern-9(11)-ene and 3,12-diketofern-9(11)-ene have been isolated from the ether extracts of the lichen Xanthoria resendei, together with peroxyergosterol and the anthraquinone pigments physcion, fallacinal and fallacinol.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.