Histochemical Studies of the Non‐Host Resistance and the Role of Actin Cytoskeleton in Pepper Against Colletotrichum orbiculare

The penetration process and defence reactions (hypersensitive response, oxidative burst and cell wall fortification) of Colletotrichum orbiculare were studied histochemically on pepper cultivar ‘A11’ (non‐host) and susceptible cucumber cultivar ‘Changchun Thorn’ (host). The results indicate that C. orbiculare could hardly penetrate the non‐host pepper leaves. It was papillae rather than hypersensitive response and H₂O₂ that played an important role in resisting the colonization and development of C. orbiculare on the non‐host pepper. The depolymerization of the actin microfilament weakened the papilla deposition of pepper and allowed successful penetration of the non‐adapted C. orbiculare, suggesting that the actin cytoskeleton of pepper is significant in preventing the invasion of the non‐host pathogen C. orbiculare.     

Human urine: Epicatechin metabolites and antioxidant activity after cocoa beverage intake

Associations between cocoa consumption in humans, excreted metabolites and total antioxidant capacity (TAC) have been scarcely investigated. The aims of the study were to investigate the epicatechin (( ? )-Ec) metabolites excreted in urine samples after an intake of 40 g of cocoa powder along with the TAC of these urine samples and the relation between both the analyses. Each of the 21 volunteers received two interventions, one with a polyphenol-rich food (PRF) and one with a polyphenol-free food (PFF) in a randomized cross-over study. Urine samples were taken before and during 24 h at 0–6, 6–12 and 12–24 h periods after test intake. The excreted ( ? )-Ec metabolites and the TAC were determined in urine samples by LC-MS/MS and TEAC assay, respectively. The maximum excretion of ( ? )-Ec metabolites and the maximum TAC value were observed in urine samples excreted between 6 and 12 h after PRF consumption. Significance of TAC increase was found in urine samples excreted during 0–6 and 6–12 h (66.6 and 72.67%, respectively, with respect to the 0 h).     

Arylguanidine and arylbiguanide binding at 5-HT3 serotonin receptors: a QSAR study

For a series of monosubstituted arylguanidines, 5-HT3 receptor affinity was found generally related to the electron withdrawing nature of the substituent at the aryl 3-position and the lipophilicity of the 4-position substituent. A broader examination of 35 arylguanidines and arylbiguanides revealed that affinity could be described by molecular polarizability, a Chi index term (8chiP), and the sum of all (-Cl) E-State values (SsCl) in the molecule.     

Revision of the section Anillochlamys Jeannel, 1909 (Coleoptera: Leiodidae: Cholevinae: Leptodirini)

The taxonomy of the Iberian Leptodirini species of the section Anillochlamys Jeannel, 1909 has been revised. The proposed classification is based on the study of the genital structures of both sexes, in particular the internal sac of the aedeagus. According to the different models of internal sacs, the following genera, species and subspecies are identified: genus Anillochlamys Jeannel, 1909: A. aurouxi Español, 1965, A. bueni Jeannel, 1909 (= A. avariae Comas, 1977 n.syn.), A. cullelli Lagar, 1978, A. moroderi Bolívar, 1923 (= A. negrei Comas, 1990 n. syn.), A. subtruncatus Jeannel, 1930 (= A. baguenai Jeannel, 1930) and A. tropicus (Abeille, 1881) (= Adelops hispanicus Ehlers, 1893; A. tropicus var. apicalis Jeannel, 1909); genus Paranillochlamys Zariquiey, 1940: P. catalonicus (Jeannel, 1913), P. urgellesi (Español, 1965) and P. velox Zariquiey, 1940 (= P. velox montadai Lagar, 1963 n. syn.); genus Pseudochlamys Comas, 1977: P. raholai (Zariquiey, 1922) (= Anillochlamys raholai luis-bofilli Zariquiey, 1940 n. syn.); genus Spelaeochlamys Dieck, 1870 (= Typhlochlamys Español, 1975 n.syn.): S.bardisai (Español, 1975) (= Typhlochlamys escolai Comas, 1978 n. syn.), S. ehlersi Dieck, 1870 and S. ehlersi verai Comas, 1977 n. stat.     

The effects of extracellular calmodulin on initiation of Hippeastrum rutilum pollen germination and tube growth

The effects of anti-calmodulin (CaM) serum, the CaM antagonist W7-agarose, the Ca²⁺ chelator ethyleneglycol-bis-(β-aminoethyl)-N,N,N′,N′-tetraacetic acid (EGTA) and exogenous pure CaM on pollen germination and tube growth of Hippeastrum rutilum Herb were studied. Pollen germination and tube growth were inhibited or completely stopped by anti-CaM serum in a dose-dependent manner, while the same amount of preimmune serum had no effect on either process. Pollen germination and tube growth were also inhibited or completely stopped by the CaM antagonist W7-agarose and the Ca²⁺ chelator EGTA. The addition of exogenous pure CaM enhanced pollen germination and tube growth, whereas the same amount of bovine serum albumin had no effect. The inhibitory effects caused by anti-CaM serum, W7-agarose and EGTA-washing could be reversed completely by the addition of exogenous pure CaM. These results indicate that extracellular CaM initiates pollen germination and tube growth, whereas exogenous CaM enhances the above processes, and may provide a novel view for understanding the control of pollen germination and tube growth. Received: 12 December 1996 / Accepted: 15 January 1997     

Structure of human cytosolic X-prolyl aminopeptidase: a double Mn(II)-dependent dimeric enzyme with a novel three-domain subunit

X-prolyl aminopeptidases catalyze the removal of a penultimate prolyl residue from the N termini of peptides. Mammalian X-prolyl aminopeptidases are shown to be responsible for the degradation of bradykinin, a blood pressure regulator peptide, and have been linked to myocardial infarction. The x-ray crystal structure of human cytosolic X-prolyl aminopeptidase (XPN-PEP1) was solved at a resolution of 1.6 angstroms. The structure reveals a dimer with a unique three-domain organization in each subunit, rather than the two domains common to all other known structures of X-prolyl aminopeptidase and prolidases. The C-terminal catalytic domain of XPNPEP1 coordinates two metal ions and shares a similar fold with other prolyl aminopeptidases. Metal content analysis and activity assays confirm that the enzyme is double Mn(II) dependent for its activity, which contrasts with the previous notion that each XPNPEP1 subunit contains only one Mn(II) ion. Activity assays on an E41A mutant demonstrate that the acidic residue, which was considered as a stabilizing factor in the protonation of catalytic residue His498, plays only a marginal role in catalysis. Further mutagenesis reveals the significance of the N-terminal domain and dimerization for the activity of XPNPEP1, and we provide putative structural explanations for their functional roles. Structural comparisons further suggest mechanisms for substrate selectivity in different X-prolyl peptidases.     

Dynamic Host Immune and Transcriptomic Responses to Respiratory Syncytial Virus Infection in a Vaccination-Challenge Mouse Model

Virologica Sinica - Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in children. Inactivated RSV vaccine was developed in the late 1960’s, but the...     

宁夏、内蒙古的一些早白垩世珠蚌类

宁夏六盘山群上部和内蒙古赛汉塔拉组产出的珠蚌类化石为首次描述,其面貌与邻区相当地层产出的蚌类相似,前人将它们鉴定为Unio。现据它们的壳顶区缺双带构造、前假主齿乳头状并不呈“多”形排列和前闭壳肌痕内具树枝状构造等特征建立Ningxiaconcha gen. nov.。本文还对Pseudelliptio属及其模式种的含义作了补充修订;通过这些珠蚌类化石的对比,宁夏六盘山群和内蒙古赛汉塔拉组可与新疆吐谷鲁群中上部、辽西沙海组和阜新组、山东蒙阴群中上部、浙江寿昌组上段以及苏联、蒙古、德国韦尔登阶进行对比,其时代应归入早白垩世早期。