Antimycobacterial dihydronaphthalenone from the endophytic fungus Nodulisporium sp. of Antidesma ghaesembilla

Two new dihydronaphthalenones (1, 2) with four known compounds (3–6) were isolated as secondary metabolites of the endophytic fungus Nodulisporium sp. from Antidesma ghaesembilla. Their chemical structures were established based on 1D and 2D NMR spectroscopic data and HR-ESI–MS analyses. The relative configuration of 2 was confirmed by single crystal X-ray crystallographic analysis. A new isofuranonaphthalenone 2 displayed antimycobacterial and antimalarial activities with IC₅₀ values of 3.125 and 11.3 μg/mL, respectively.     

The oldest illustration of Chinese crinoid calyx: Annotated translation of “Cupressocrinus abbreviatus” reported by Fritz Frech in 1911

The early history on the discovery of the first Chinese crinoid calyx of “Cupressocrinus abbreviatus” (now Halocrinites schlotheimii Steininger, 1831) remains unclear. The first record of “C. abbreviatus” was reported by Fritz Frech in 1911. It was included in the fifth and the last volume of the series titled China by the German traveler and explorer Ferdinand Freiherr von Richthofen. The cover page, title page, and prologue are informative; thus, they are explained and translated in detail. Richthofen's specimen is still the oldest documented cupressocrinitid calyx known in China today. Discovery of a second cupressocrinitid specimen confirms the existence of this family in China. Current taxonomic positions of the Chinese specimens are discussed.     

The forest resources input–output model: An application in China

Understanding the state of forest resource utilization in China and correctly evaluating the role and function of forest resources in national economic development are essential for realizing balanced development of forests, the environment, and the economy. This is especially true given the present situation of increasingly scarce forest resources. Using data from Chinese forest industry statistical yearbooks, forestry development reports, and other documents, this paper examines the current state of forest resource utilization in China from the angle of combining quantities and values based on input–output tables. We show that demand for and input use of forest resources varies greatly across industrial sectors; the paper products and furniture manufacturing industries have the greatest direct consumption coefficient for timber use. When considering direct and indirect demand, it is clear that forest resources restrict different industrial sectors in diverse ways. These results provide an important set of reference values regarding the utilization of forest resources and coordinated industrial development in China.     

Biochemical and physiological characterization of a new Na+-channel specific peptide from the venom of the Argentinean scorpion Tityus trivittatus

A new peptide with 61 amino acids cross-linked by 4 disulfide bridges, with molecular weight of 6938.12 Da, and an amidated C-terminal amino acid residue was purified and characterized. The primary structure was obtained by direct Edman degradation and sequencing its gene. The peptide is lethal to mammals and was shown to be similar (95% identity) to toxin Ts1 (gamma toxin) from the Brazilian scorpion Tityus serrulatus; it was named Tt1g (from T. trivittatus toxin 1 gamma-like). Tt1g was assayed on several sub-types of Na⁺-channels showing displacement of the currents to more negative voltages, being the hNav1.3 the most affected channel. This toxin displays characteristics typical to the β-type sodium scorpion toxins. Lethality tests and physiological assays indicate that this peptide is probably the most important toxic component of this species of scorpion, known for causing human fatalities in the South American continent.     

Histidine-rich glycoprotein blocks collagen-binding integrins and adhesion of endothelial cells through low-affinity interaction with α2 integrin

The plasma protein histidine-rich glycoprotein (HRG) affects the morphology and function of both endothelial cells (ECs) and monocytes/macrophages in cancer. Here, we examined the mechanism of action of HRG's effect on ECs. HRG suppressed adhesion, spreading and migration of ECs specifically on collagen I (COL I) whereas ECs seeded on other extracellular matrix proteins were insensitive to HRG. HRG did not bind specifically to COL I or to the α-integrin binding site on collagen, GFOGER. Furthermore, HRG's inhibition of EC adhesion was not dependent upon heparan sulfate (HS) moieties as heparitinase-treated ECs remained sensitive to HRG. C2C12 cells expressing α2 integrin, the major collagen-binding α-integrin subunit in ECs, showed increased binding of HRG compared with wild type C2C12 cells lacking the α2 subunit. Recombinant α2 I-domain protein bound HRG and to a higher extent when in active conformation. However, the α2 I-domain bound weakly to HRG compared with COL I and the purified α2β1 ectodomain complex failed to retain HRG. We conclude that HRG binds to α2 integrin through low-affinity interactions in a HS-independent manner, thereby blocking EC-adhesion to COL I.     

Phytochemical and chemotaxonomic study on Ficus tsiangii Merr. ex Corner

Thirty-four compounds, including ten coumarins (1–10), thirteen flavonoids (11–23), three triterpenoid, one lignanoid (24), seven triterpenes (25–31) and three other compounds (32–34), were isolated from the stems of Ficus tsiangii Merr. ex Corner (F. tsiangii). Their structures were identified as xanthyletin (1), coumarin (2), umbelliferone (3), isoangenomalin (4), dihydroxanthyletin (5), scopoletin (6), nodakenetin (7), 6,7-dihydroxy-coumarin (8), 4'-O-β- glucopyranosyl-3'-hydroxy-nodakenetin (9), 6-carboxy-umbelliferone (10), 5,7,4'-trimethoxy- 3'-hydroxy-aurone (11), apigenin (12), naringenin (13), genistein (14), luteolin (15), prunetin (16), chrysoeriol (17), 5,6,7,-trihydroxy-4'-methoxy-flavone (18), eriodictyol (19), isocarthamidin (20), 5,7,2',4'-tetrahydroxyflavone (21), taxifolin (22), dihydro-kaempferol (23), syringeresinol (24), taraxerol (25), taraxerone (26), lupeolacetate (27), 3-acetoxy-12- oleanene-11-ketone (28), 3-acetoxy-lup-12,20(29)-diene (29), oleanic acid (30), ursolic acid (31), 3,4,5-trimethoxy phenyl-1-O-glucopyranoside (32), 8'-hydroxyabscisic acid glucoside (33) and adenosine (34). Among them, all compounds except 3, 14, 17, 25, 26, 30, 33 were isolated from the plant for the first time, and compounds 1, 4, 5, 8–11, 16, 18, 20, 23, 24, 32, 34 were firstly reported from the genus Ficus. The chemotaxonomic significance of these compounds was summarized as follows.     

SIPL1-facilitated PTEN ubiquitination contributes to its association with PTEN

PTEN is post-translationally modified by ubiquitin via association with multiple E3 ubiquitin ligases, including NEDD4-1, XIAP, and WWP2. Despite the rapid progress made in researching the impact of ubiquitination on PTEN function, our understanding remains fragmented. Building on the previously observed interaction between SIPL1 and PTEN, we report here that SIPL1 promotes PTEN polyubiquitination via lysine 48 (K48)-independent polyubiquitin chains. Substitution of the K48 residue of ubiquitin with arginine (R) enhanced SIPL1-mediated PTEN polyubiquitination. In contrast, the K63R substitution significantly reduced it. The ubiquitin-like (UBL) domain is required for SIPL1-induced PTEN polyubiquitination. This post-translational modification promoted the association of SIPL1 with PTEN. Elevated amounts of the SIPL1/PTEN complex were precipitated in 293T cells co-transfected with PTEN, SIPL1, and ubiquitin compared to cells co-transfected with SIPL1 and PTEN only. Additionally, formation of the SIPL1/PTEN complex was inhibited when either lysine-less (K0) ubiquitin or K63R ubiquitin was co-transfected together with SIPL1 + PTEN. The PTEN component in the SIPL1/PTEN complex contained polyubiquitin chains. The ubiquitination reaction may play a structural role, stabilizing the SIPL1/PTEN complex, as a ubiquitin binding-defective SIPL1 mutant (TFLV) is proficient in PTEN association. Collectively, we demonstrate that SIPL1 binds PTEN and enhances PTEN polyubiquitination which in turn promotes the interaction between SIPL1 and PTEN.     

Synthesis of isochroman-4-ones and 2H-pyran-3(6H)-ones by gold-catalyzed oxidative cycloalkoxylation of alkynes

Gold catalysis is a convenient tool to oxidatively functionalize alkyne into a range of valuable compounds. In this article, we report a new access to isochroman-4-one and 2H-pyran-3(6H)-one derivatives that involves a gold-catalyzed oxidative cycloalkoxylation of an alkyne in the presence of a pyridine N-oxide. The reaction proceeds under mild conditions, is relatively efficient and exhibits a high functional group compatibility.