Impaired cognitive function and reduced anxiety‐related behavior in a promyelocytic leukemia (PML) tumor suppressor protein‐deficient mouse

The promyelocytic leukemia (PML) protein is a tumor suppressor factor mostly known by its involvement in acute promyelocytic leukemia (APL). Interestingly, recent studies have provided evidence that, in the central nervous system, PML is involved in neurogenesis. However, prospective studies of PML in brain are lacking. To further understand the role of PML in the mammalian brain, we studied plasticity and behavioral changes in PML knockout mice. If PML is involved in neurogenesis, and neurogenesis is an important process for proper brain development as well as learning and memory functions, we hypothesized that PML might have a role in plasticity and cognition. Behavioral studies demonstrated that PML knockout mice present abnormalities in conditioned learning and spatial memory, as determined by fear conditioning and Morris water maze tasks. Experiments to determine normal exploratory behavior interestingly revealed that PML knockout mice present reduced anxiety‐related responses as compared to control animals. This was confirmed when PML knockout mice spent more time in the open arms of an elevated plus‐maze, which is an indication of decreased anxiety. Additionally, impairments in hippocampus‐dependent learning were mirrored by altered long‐term plasticity at Schaffer collateral‐CA1 synapses. We now provide the first evidence for an important role of PML in the brain, indicating that PML might have a role in synaptic plasticity and associated behavioral processes.     

Chemical Diversity of the Natural Populations of Dalmatian Pyrethrum (Tanacetum cinerariifolium (Trevir.) Sch.Bip.) in Croatia

Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevir. ) Sch.Bip. ) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households. A total of 25 Dalmatian pyrethrum populations from Croatia were studied to determine the pyrethrin content and composition, and to identify distinct chemotypes. The total pyrethrin content ranged from 0.36 to 1.30% (dry flower weight; DW) and the pyrethrin I/pyrethrin II ratio ranged from 0.64 to 3.33%. The statistical analyses revealed that the correlations between the percentage of pyrethrin I and of all the other components were significant and negative. The total pyrethrin content was positively correlated with the percentage of pyrethrin I and negatively correlated with cinerin II. The multivariate analysis of the chemical variability enabled the identification of five chemotypes among 25 Dalmatian pyrethrum populations. The chemical characterization of indigenous Dalmatian pyrethrum populations may serve as a good background for future breeding and agricultural exploitation.     

Simultaneous RP‐HPLC‐DAD Separation,and Determination of Flavonoids and Phenolic Acids in Plantago L. Species

A rapid reversed‐phase (RP) high‐performance liquid chromatography method was developed and applied for simultaneous separation, and determination of flavonoids and phenolic acids in eight Plantago L. taxa (P. altissima L., P. argentea Chaix , P. coronopus L., P. holosteum Scop . ssp. depauperata Pilger , P. holosteum ssp. holosteum, P. holosteum ssp. scopulorum (Degen) Horvati? , P. lagopus L., and P. maritima L.) growing in Croatia. Chromatographic separation was carried out on Zorbax Eclipse XDB‐C18 using gradient elution with a H₂O (pH 2.5, adjusted with CF₃COOH) and MeCN mixture at 30°. The contents of analyzed phenolic compounds (% of the dry weight of the leaves, dw) varied among examined species: rutin (max. 0.024%, P. argentea), hyperoside (max. 0.020%, P. lagopus), quercitrin (max. 0.013%, P. holosteum ssp. holosteum), quercetin (max. 0.028%, P. holosteum ssp. scopulorum), chlorogenic acid (max. 0.115%, P. lagopus), and caffeic acid (max. 0.046%, P. coronopus). Isoquercitrin was detected only in P. argentea (0.020%), while isochlorogenic acid content was below limit of quantification in all investigated species. Multivariate analyses (UPGMA and PCA) showed significant differences in contents of investigated polyphenolic compounds between different Plantago taxa. Accordingly, investigated substances might be employed as chemotaxonomic markers in the study of the complex genus Plantago.     

Chemical Constituents from a Soil‐Derived Actinomycete,Actinomadura miaoliensis BCRC 16873, and Their Inhibitory Activities on Lipopolysaccharide‐Induced Tumor Necrosis Factor Production

An investigation on the secondary metabolites from the BuOH extract of the fermentation broth of the thermotolerant polyester‐degrading actinomycete Actinomadura miaoliensis BCRC 16873 was carried out. One previously undescribed α‐pyrone (=pyran‐2‐one) derivative, designated as miaolienone ( 1 ), and a new butanolide, miaolinolide ( 2 ), together with 13 known compounds, 3 – 15 , were obtained. Their structures were established on the basis of extensive 1D‐ and 2D‐NMR analyses in combination with HR‐MS experiments. In addition, the isolated compounds 1 – 15 were evaluated for the inhibitory effects of the isolates on the production of tumor necrosis factor (TNF‐α) induced by lipopolysaccharide (LPS). Among the isolates, 1 and 2 significantly inhibited TNF‐α production in U937 cells in vitro, and the IC₅₀ values were 0.59 and 0.76 μM , respectively. Compounds 3 – 5 displayed moderate inhibitory activities on LPS‐induced TNF‐α production.     

Pierisformotoxins A – D,Polyesterified Grayanane Diterpenoids from Pieris formosa and Their cAMP‐Decreasing Activities

Four highly acylated diterpenoids, designated as pierisformotoxins A–D ( 1 – 4 , resp.), along with 26 known compounds, were isolated from the flowers of Pieris formosa. Among them, pierisformotoxins A and B ( 1 and 2 , resp.) were new highly acylated grayanane diterpenoids, of which the five‐membered ring A has undergone an oxidative cleavage between C(3) and C(4), followed by lactonization, to give rise to a five‐membered lactone ring between C(3) and C(5), differing from the previously reported grayanane diterpenoids with a 5/7/6/5 ring system. Results of the cAMP‐regulation‐activity assay showed that pierisformotoxin C ( 3 ) at 10 μM (inhibitory ratio (IR): 10.1%) or 2 μM (9.8%), and pierisformotoxin B ( 2 ) at 50 μM (13.9%) significantly decreased the cAMP level in N1E‐115 neuroblastoma cells (p<0.05).     

Permeation through Phospholipid Bilayers,Skin‐Cell Penetration,Plasma Stability,and CD Spectra of α‐ and β‐Oligoproline Derivatives

After a survey of the special role, which the amino acid proline plays in the chemistry of life, the cell‐penetrating properties of polycationic proline‐containing peptides are discussed, and the widely unknown discovery by the Giralt group (J. Am. Chem. Soc. 2002 , 124, 8876) is acknowledged, according to which fluorescein‐labeled tetradecaproline is slowly taken up by rat kidney cells (NRK‐49F). Here, we describe details of our previously mentioned (Chem. Biodiversity 2004 , 1, 1111) observation that a hexa‐β³‐Pro derivative penetrates fibroblast cells, and we present the results of an extensive investigation of oligo‐L ‐ and oligo‐D ‐α‐prolines, as well as of oligo‐β²h‐ and oligo‐β³h‐prolines without and with fluorescence labels ( 1 – 8 ; Fig. 1). Permeation through protein‐free phospholipid bilayers is detected with the nanoFAST biochip technology (Figs. 2–4). This methodology is applied for the first time for quantitative determination of translocation rates of cell‐penetrating peptides (CPPs) across lipid bilayers. Cell penetration is observed with mouse (3T3) and human foreskin fibroblasts (HFF; Figs. 5 and 6–8, resp.). The stabilities of oligoprolines in heparin‐stabilized human plasma increase with decreasing chain lengths (Figs. 9–11). Time‐ and solvent‐dependent CD spectra of most of the oligoprolines (Figs. 13 and 14) show changes that may be interpreted as arising from aggregation, and broadening of the NMR signals with time confirms this assumption.     

Triterpenoids from the Stem Bark of Melia toosendan and Determination of Their Absolute Configurations at C(24)

Six new triterpenoids, meliasenins S–X ( 1 – 6 , resp.), were isolated from the stem bark of Melia toosendan. Their structures were elucidated by mass spectrometry, NMR experiments, and comparison with the known compounds. Particularly, the absolute configuration at C(24) in new compounds was determined through their CD spectra of the [Pr(FOD)₃] complex (fod=1,1,1,2,2,3,3,7,7,7‐decafluoroheptane‐4,6‐dione) in CCl₄, as well as by using Mosher's method.