Host density drives the postglacial migration of the tree parasite,Epifagus virginiana

To survive changes in climate, successful species shift their geographic ranges to remain in suitable habitats. For parasites and other highly specialized species, distributional changes not only are dictated by climate but can also be engineered by their hosts. The extent of host control on parasite range expansion is revealed through comparisons of host and parasite migration and demographic histories. However, understanding the codistributional history of entire forest communities is complicated by challenges in synthesizing datasets from multiple interacting species of differing datatypes. Here we integrate genetic and fossil pollen datasets from a host–parasite pair; specifically, the population structure of the parasitic plant (Epifagus virginiana) was compared with both its host (Fagus grandifolia) genetic patterns and abundance data from the paleopollen record of the last 21,000 y. Through tests of phylogeographic structure and spatial linear regression models we find, surprisingly, host range changes had little effect on the parasite''s range expansion and instead host density is the main driver of parasite spread. Unlike other symbionts that have been used as proxies to track their host''s movements, this parasite''s migration routes are incongruent with the host and instead reflect the greater importance of host density in this community''s assembly. Furthermore, these results confirm predictions of disease ecological models regarding the role of host density in the spread of pathogens. Due to host density constraints, highly specialized species may have low migration capacities and long lag times before colonization of new areas.     

Chemical Constituents from Stems of Cistanches deserticola

Objective To study the chemical constituents in the stems of Cistanches deserticola. Methods The compounds were purified by various column chromatographic methods and their structures were elucidated by spectroscopic(1D, 2D NMR, IR, [?]D, and MS) and chemical analyses. Results Seven compounds were isolated and identified as kankanoside D1(1), ajugol(2), cistanin(3), uridine(4), adenosine(5), 6-deoxycatalpol(6), and kankanoside D(7). Conclusion Compound 1 is a new compound.     

丁座草的化学成分研究

目的 研究丁座草块茎的化学成分。方法用色谱方法分离丁座草块茎的乙醇提取物。结果 共分离得到8个化合物，根据理化性质及各种光谱技术进行结构鉴定，分别为α-香树素（Ⅰ）、3β-乙酰氧基-熊果-28，13-内酯（11）、3β-乙酰氧基-熊果-11（12）-烯-28，13-内酯（Ⅲ）、3β-乙酰熊果酸（Ⅳ）、3β-乙酰齐墩果酸（V）、β-谷甾醇（Ⅵ）、熊果酸（Ⅶ）、（＋）-松脂素单葡萄糖苷（Ⅷ）。结论 化合物Ⅰ～Ⅲ为首次从该属植物中分离得到。     

Chemical constituents of Cistanche sinensis

One new phenylethanoid glycoside, cistansinenside A and one new oligosaccharide, cistansinensose A₁/A₂, were isolated from the stems of Cistanche sinensis, together with six known compounds. The structures of the new compounds were elucidated on the basis of spectral data.     

蒙药列当的化学成分研究

目的:研究蒙药列当(Orobanche coerulescens Steph)的化学成分,为进一步明确其中的有效成分奠定基础。方法:利用普通硅胶柱色谱、大孔树脂柱色谱、Sephadex LH-20色谱技术及重结晶等方法进行分离、纯化,并利用波谱技术和理化性质确定了化合物的结构。结果:从中分离得到9个化合物,分别鉴定为:甘露醇①,β-谷甾醇②,豆甾醇③,二十烷酸-1-甘油酯④,β-胡萝卜苷⑤,琥珀酸⑥,Crenatoside⑦,麦角甾苷⑧,D-松醇⑨。结论:其中化合物③,④,⑦,⑧,⑨为首次从该植物中获得。     

Chemical constituents of Cistanche sinensis

One new phenylethanoid glycoside, cistansinenside A and one new oligosaccharide, cistansinensose A₁/A₂, were isolated from the stems of Cistanche sinensis, together with six known compounds. The structures of the new compounds were elucidated on the basis of spectral data.     

Cytotoxic and antioxidant activities of selected Lamiales species from Mexico

Context: Methanol extracts obtained from eight species belonging to four families of the Lamiales order native to Mexico were investigated for biological action.

Objective: Cytotoxicity and antioxidant activity of methanol extracts have been investigated.

Materials and methods: Cytotoxic activity was evaluated by the sulphorhodamine B protein staining assay against KB (nasopharyngeal), HEp-2 (larynx), HF-6 (colon), MCF7 (breast), PC-3 (prostate), and Ca Ski (cervix) carcinoma cell lines. To analyze the antioxidant activity, common stable radicals chromogens, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS^·+) and DPPH (1,1-diphenyl-2-picrylhydrazyl) were used. The ferric reducing antioxidant power (FRAP) and the total phenolic content of the samples were also determined.

Results: Some of the extracts, such as Limosella aquatica L. (Scrophulariaceae), Mimulus glabratus Kunth. (Phrymaceae), Pedicularis mexicana Zucc. ex Benth. (Orobanchaceae), and Penstemon campanulatus (Cav.) Willd. (Plantaginaceae) displayed remarkably selective cytotoxic activity. However, the extract from Veronica americana (Raf.) Schwein (Plantaginaceae) showed the highest activity with IC₅₀ values of 1.46 and 0.169 μg/mL on PC-3 and HF-6 cells, respectively. With the exception of M. glabratus, all the extracts showed different degrees of antioxidant activity with IC₅₀ values from 0.89 up to 1.8 in the ABTS assay; from 0.49 up to 1.25?mg/mL in the DPPH assay and with the FRAP evaluation, 36 to 68 equivalents in mM of FeSO₄. V. americana also showed the highest antoxidant activity with IC₅₀ values from 0.491 and 0.892?mg/mL, on DPPH and ABTS assays, respectively.

Discussion and conclusion: These findings demonstrated that the species studied have great potential cytotoxic and antioxidant activity.     

Iridoid compounds fromBoschniakia rossica

Four iridoid compounds were isolated from methanol extract of Boschniakia rossica by repeated column chromatography. Their structures were determined as boschnaloside (1), boschnarol (2), bosnarol methylether (3), and 7-deoxy 8-epiloganic acid (4), respectively. Compound 2, 3, and 4 were isolated for the first time from this plant.     

Protective effect of Cistanche deserticola on gentamicin-induced nephrotoxicity in rats

Objective: Gentamicin (GM) is a commonly used aminoglycoside antibiotic, however, renal toxicity has limited its usage. The present study was designed to evaluate the ameliorative effect of Cistanche deserticola on GM-induced nephrotoxicity in rats. Methods: The nephrotoxicity in rats was induced by intraperitoneal administration of GM (100 mg/kg) for 10 consecutive days. Glomerular filtration rate, blood urea nitrogen, creatinine and kidney histopathology were detected to assess the GM-induced nephrotoxicity. The oxidative stress (catalase, superoxide dismutase, glutathione and malondialdehyde) was assessed. The inflammatory response (tumor necrosis factor-α, interleukin-6, myeloperoxidase and nuclear factor-kappa B) and apoptotic marker (Bax and Bcl-2) were also evaluated. Results: The results showed that water and 75% ethanol extracts of C. deserticola (named CDW and CDE, respectively) (100, 200 and 400 mg/kg) in combination with GM could recover the reduction of glomerular filtration rate and enhance the renal endogenous antioxidant capability induced by GM. The increase in the expression of renal inflammatory cytokines (tumor necrosis factor-α and interleukin-6), nuclear protein of nuclear factor-kappa B (p65) and the activity of myeloperoxidase induced by GM was significantly decreased upon CDW or CDE treatment. In addition, CDW or CDE treatment could decrease the Bax protein expression and increase the Bcl-2 protein expression in GM-induced nephrotoxicity in rats significantly. Conclusion: The study demonstrated that C. deserticola treatment could attenuate kidney dysfunction and structural damage in rats induced by GM through the reduction of inflammation, oxidative stress and apoptosis.     

国产列当科肉苁蓉属的分类学研究

本文在详细回顾肉苁蓉属分类历史的基础上 ,对中国列当科肉苁蓉属进行了分类学研究 ,共记载 5种该属植物 ,并澄清了一些混淆的属的中文名称和错误鉴定。