Tirucallane triterpenoids from the stem bark of Araliopsis synopsis

Two new tirucallane triterpenoids, 21-methoxy-21,23-epoxy-tirucalla-7,24-dien-3α-ol (1) and 21-methoxy-21,23-epoxy-tirucalla-7,24-diene-1α,3α-diol (2), together with thirteen known compounds were isolated from the CH₂Cl₂ extract of the stem bark of Araliopsis synopsis. The structures of the compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral (EI and ESI) data and comparison with previously known analogs. Compounds 1–10 were tested against bacteria, fungi and plant pathogen oomycetes by the paper disk agar diffusion assay resulting in missing to low activities corresponding with MICs > 1 mg/mL. However, compounds 5–10 exhibited high cytotoxic activity against the human Caucasian prostate adenocarcinoma cell PC-3 line, with IC₅₀ 8.5–12.5 μM compared to the standard Doxorubicin with IC₅₀ = 0.9 μM, while compounds 1, 3 and 4 showed low activity.     

Increase trend of correlation and phase synchrony of microwire iEEG before macroseizure onset

Micro/macrowire intracranial EEG (iEEG) signals recorded from implanted micro/macroelectrodes in epileptic patients have received great attention and are considered to include much information of neuron activities in seizure transition compared to scalp EEG from cortical electrodes. Microelectrode is contacted more close to neurons than macroelectrode and it is more sensitive to neuron activity changes than macroelectrode. Microwire iEEG recordings are inevitably advantageous over macrowire iEEG recordings to reveal neuronal mechanisms contributing to the generation of seizures. In this study, we investigate the seizure generation from microwire iEEG recordings and discuss synchronization of microwire iEEGs in four frequency bands: alpha (1−30 Hz), gamma (30−80 Hz), ripple (80–250 Hz), and fast ripple (>250 Hz) via two measures: correlation and phase synchrony. We find that an increase trend of correlation or phase synchrony exists before the macroseizure onset mostly in gamma and ripple bands where the duration of the preictal states varied in different seizures ranging up to a few seconds (minutes). This finding is contrast to the well-known result that a decrease of synchronization in macro domains exists before the macroseizure onset. The finding demonstrates that it is only when the seizure has recruited enough surrounding brain tissue does the signal become strong enough to be observed on the clinical macroelectrode and as a result support the hypothesis of progressive coalescence of microseizure domains. The potential ramifications of such an early detection of microscale seizure activity may open a new window on treatment by making possible disruption of seizure activity before it becomes fully established.     

Residue Val237 is critical for the enantioselectivity of Penicillium expansum lipase

The shape of the hydrophobic tunnel leading to the active site of Penicillium expansum lipase (PEL) was redesigned by single-point mutations, in order to better understand enzyme enantioselectivity towards naproxen. A variant with a valine-to-glycine substitution at residue 237 exhibited almost no enantioselectivity (E = 1.1) compared with that (E = 104) of wild-type PEL. The function of the residue, Val237, in the hydrophobic tunnel was further analyzed by site-directed mutagenesis. For each of these variants a significant decrease of enantioselectivity (E < 7) was observed compared with that of wild-type enzyme. Further docking result showed that Val237 plays the most important role in stabilizing the correct orientation of (R)-naproxen. Overall, these results indicate that the residue Val237 is the key amino acid residue maintaining the enantioselectivity of the lipase.     

A comparative study of the effects of abscisic acid and methyl jasmonate on seedling growth of rice

The effects of abscisic acid (ABA) and methyl jasmonate (MJ) on growth of rice seedlings were compared. The lowest tested concentration of ABA and MJ that inhibited seedling growth was found to be 4.5 and 0.9 µM, respectively. Growth inhibition by ABA is reversible, whereas that by MJ is irreversible. GA₃ was found to be more effective in reversing inhibition of shoot growth by ABA than by MJ. KCl partially relieved MJ-inhibited, but not ABA-inhibited, growth of rice seedlings. The beneficial effect of K⁺ on growth of rice seedlings in MJ medium could not be replaced by Li⁺, Na⁺ or Cs⁺. MJ treatment caused a marked release of K⁺ into the medium. In order to understand whether cell wall-bound peroxidase activity was inversely related to rice seedling growth, effects of ABA and MJ on cell wall-bound peroxidase activity were also examined. Results indicated that both ABA and MJ increased cell wall-bound peroxidase activity in roots and shoots of rice seedlings. Although MJ (4.5 µM) was less effective in inhibiting root growth than ABA (9 µM), MJ was found to increase more cell wall-bound peroxidase activity in roots than ABA.     

Soluble Fas ligand induces epithelial cell apoptosis in humans with acute lung injury (ARDS).

The goals of this study were to determine whether the Fas-dependent apoptosis pathway is active in the lungs of patients with the acute respiratory distress syndrome (ARDS), and whether this pathway can contribute to lung epithelial injury. We found that soluble Fas ligand (sFasL) is present in bronchoalveolar lavage (BAL) fluid of patients before and after the onset of ARDS. The BAL concentration of sFasL at the onset of ARDS was significantly higher in patients who died. BAL from patients with ARDS induced apoptosis of distal lung epithelial cells, which express Fas, and this effect was inhibited by blocking the Fas/FasL system using three different strategies: anti-FasL mAb, anti-Fas mAb, and a Fas-Ig fusion protein. In contrast, BAL from patients at risk for ARDS had no effect on distal lung epithelial cell apoptosis. These data indicate that sFasL is released in the airspaces of patients with acute lung injury and suggest that activation of the Fas/FasL system contributes to the severe epithelial damage that occurs in ARDS. These data provide the first evidence that FasL can be released as a biologically active, death-inducing mediator capable of inducing apoptosis of cells of the distal pulmonary epithelium during acute lung injury.     

强旱生小灌木绵刺劈裂生长过程中内源激素含量变化的研究

 研究强旱生小灌木绵刺(Potaninia mongolica)劈裂生长过程中内源激素含量的变化。结果表明：1）4种生长状态中,完全劈裂的植株的叶片及劈裂发生部位ABA的含量比其它3种状态的都低,而其根中ABA的含量最大。同其它几种激素相比,ABA在绵刺体内的含量最大;2）劈裂生长发生之前,在劈裂发生部位IAA积累量大,尤其是在即将劈裂的过渡植株的劈裂发生部位IAA含量最大;3）劈裂生长发生过程中GA3含量的变化与IAA的变化有同步性;4）ZR的含量也是在劈裂生长发生前的绵刺的劈裂发生部位中较大,随着劈裂生长的发生,植物从根部向叶片及劈裂发生部位运输的ZR有逐渐降低的趋势,而在劈裂生长发生的过渡阶段,ZR从根部向劈裂发生部位运输的比例较大,分别为19.44%和20%;5）IAA、GA3、ZR 三者协调促进劈裂发生部位细胞的生长和分裂,而ABA的积累对绵刺适应干旱的环境条件起到了一定的调节作用。     

The redder the better: wing color predicts flight performance in monarch butterflies

The distinctive orange and black wings of monarchs (Danaus plexippus) have long been known to advertise their bitter taste and toxicity to potential predators. Recent work also showed that both the orange and black coloration of this species can vary in response to individual-level and environmental factors. Here we examine the relationship between wing color and flight performance in captive-reared monarchs using a tethered flight mill apparatus to quantify butterfly flight speed, duration and distance. In three different experiments (totaling 121 individuals) we used image analysis to measure body size and four wing traits among newly-emerged butterflies prior to flight trials: wing area, aspect ratio (length/width), melanism, and orange hue. Results showed that monarchs with darker orange (approaching red) wings flew longer distances than those with lighter orange wings in analyses that controlled for sex and other morphometric traits. This finding is consistent with past work showing that among wild monarchs, those sampled during the fall migration are darker in hue (redder) than non-migratory monarchs. Together, these results suggest that pigment deposition onto wing scales during metamorphosis could be linked with traits that influence flight, such as thorax muscle size, energy storage or metabolism. Our results reinforce an association between wing color and flight performance in insects that is suggested by past studies of wing melansim and seasonal polyphenism, and provide an important starting point for work focused on mechanistic links between insect movement and color.     

Synthesis and evaluation of a bifunctional chelate for development of Bi(III)-labeled radioimmunoconjugates

A new bifunctional ligand C-DEPA was designed and synthesized as a component for antibody-targeted radiation therapy (radioimmunotherapy, RIT) of cancer. C-DEPA was conjugated to a tumor targeting antibody, trastuzumab, and the corresponding C-DEPA-trastuzumab conjugate was evaluated for radiolabeling kinetics with ^205/6Bi. C-DEPA-trastuzumab conjugate rapidly bound ^205/6Bi, and ^205/6Bi-C-DEPA-trastuzumab conjugate was stable in human serum for 72 h. The in vitro radiolabeling kinetics and serum stability data suggest that C-DEPA is a potential chelate for preclinical RIT applications using ²¹²Bi and ²¹³Bi.