Orally administrated cinnamon extract reduces β-amyloid oligomerization and corrects cognitive impairment in Alzheimer's disease animal models

An increasing body of evidence indicates that accumulation of soluble oligomeric assemblies of β-amyloid polypeptide (Aβ) play a key role in Alzheimer's disease (AD) pathology. Specifically, 56 kDa oligomeric species were shown to be correlated with impaired cognitive function in AD model mice. Several reports have documented the inhibition of Aβ plaque formation by compounds from natural sources. Yet, evidence for the ability of common edible elements to modulate Aβ oligomerization remains an unmet challenge. Here we identify a natural substance, based on cinnamon extract (CEppt), which markedly inhibits the formation of toxic Aβ oligomers and prevents the toxicity of Aβ on neuronal PC12 cells. When administered to an AD fly model, CEppt rectified their reduced longevity, fully recovered their locomotion defects and totally abolished tetrameric species of Aβ in their brain. Furthermore, oral administration of CEppt to an aggressive AD transgenic mice model led to marked decrease in 56 kDa Aβ oligomers, reduction of plaques and improvement in cognitive behavior. Our results present a novel prophylactic approach for inhibition of toxic oligomeric Aβ species formation in AD through the utilization of a compound that is currently in use in human diet.     

Current Thoughts in Fungal Keratitis: Diagnosis and Treatment

Fungal keratitis remains a challenging and often elusive diagnosis in geographic regions where it is endemic. Marred by delays in diagnosis, the sequelae of corneal fungal infections, though preventable, can be irreversible. Recent studies and advances in the arena have broadened the approach and treatment to mycotic keratitis. This review will discuss current diagnostic modalities of fungal keratitis and will particularly focus on treatment regimens. It will also explore future therapeutic models and critique the potential benefit of each.     

Seasonal fires shape the germinable soil seed bank community in eastern Mediterranean woodlands

季节性火烧塑造了东地中海地区林地的可萌发种子库群落 本研究探索了在典型东地中海林地中，季节性火烧是否以及如何与微生境类型(即黄连木属(Pistacia)灌木下、岩蔷薇属(Cistus)灌木下或林冠间隙)相互作用，从而影响可萌发种子库(germinable soil seed bank, GSSB)群落的组成。我们进行了一项野外实验，其中包括预定的春秋火烧，然后利用从火烧地块和相邻未火烧对照地收集的土壤样本对种子萌发的模式进行定量。研究结果表明，秋烧期间，土壤温度比春烧的要高，而春烧期间土壤温度则比秋烧的变化更大。火烧导致可萌发种子库整体的密度、丰富性和多样性降低。秋烧地块内黄连木属和岩蔷薇属灌木的可萌发种子库丰富性和多样性显著降低，这些模式主要表现在一年生植物中。在火烧样地收集的样本中，低矮灌木的可萌发种子库密度更高，在黄连木属和岩蔷薇属灌木下采集的样品中，这种模式更为明显。在季节性火烧与出现的独特物种会共同导致可萌发种子库的群落组成发生显著的变化。这些结果表明，季节性火烧与空间异质性互相作用，主要通过对一年生植物和低矮灌木的可萌发密度的差异效应来影响可萌发种子库群落的组成。这些研究发现意味着，过去几十年东地中海盆地的季节性火烧频率上升，可能转化为进化生态选择压力的变化，并对这一独特生态系统内的植物产生影响。     

Domestication of micropropagated plants of the spice damiana (Turnera diffusa)

Tissue culture propagation was performed on the spice shrub damiana (Turnera diffusa. Willd.) using MS medium (Murashige and Skoog 1962) supplemented with different combinations of the plant growth regulators, 6-benzyl adenine (BA) and indole-3-butyric acid (IBA). Organogenesis of leaf explants from wild plants and explants from propagated cuttings was compared; only the former regenerated complete plants. The highest shooting rate (92%) occurred at a concentration of 10^–7 M BA plus 10^–6 M IBA. Regenerated shoots were rooted in MS medium without any plant growth regulators. Foliage productivity of the micropropagated plants under field cultivation was determined yearly over 3 years. The yield increased annually for the first two years. The quantity of essential oils in propagated plants was similar to that of wild plants growing nearby. We propose tissue culture propagation of damiana as a viable means of domestication of this wild plant for semi-arid agriculture in Mexico. Commercial propagation would help to conserve wild populations of damiana that are currently threatened by overharvesting.Abbreviations BA 6-benzyl adenine - IBA indole-3-butyric acid     

A Cross Modal Performance-Based Measure of Sensory Stimuli Intricacy

We define a new measure of sensory stimuli which has the following properties: It is cross modal, performance based, robust, and well defined. We interpret this measure as the intricacy or complexity of the stimuli, yet its validity is independent of its interpretation. We tested the validity and cross modality of our measure using three olfactory and one visual experiment. In order to test the link between our measure and cognitive performance we also conducted an additional visual experiment. We found that our measure is correlated with the results of the well-established Rapid Serial Visual Presentation masking experiment. Specifically, ranking stimuli according to our measure was correlated at r = 0.75 (p < 0.002) with masking effectiveness. Thus, our novel measure of sensory stimuli provides a new quantitative tool for the study of sensory processing.     

GLUT4 repression in response to oxidative stress is associated with reciprocal alterations in C/EBP alpha and delta isoforms in 3T3-L1 adipocytes

Insulin responsiveness of adipocytes is acquired during normal adipogenesis, and is essential for maintaining whole-body insulin sensitivity. Differentiated adipocytes exposed to oxidative stress become insulin resistant, exhibiting decreased expression of genes like the insulin-responsive glucose transporter GLUT4. Here we assessed the effect of oxidative stress on DNA binding capacity of C/EBP isoforms known to participate in adipocyte differentiation, and determine the relevance for GLUT4 gene regulation. By electrophoretic mobility shift assay, nuclear proteins from oxidized adipocytes exhibited decreased binding of C/EBPalpha-containing dimers to a DNA oligonucleotide harboring the C/EBP binding sequence from the murine GLUT4 promoter. C/EBPdelta-containing dimers were increased, while C/EBPbeta-dimers were unchanged. These alterations were mirrored by a 50% decrease and a 2-fold increase in the protein content of C/EBPalpha and C/EBPdelta, respectively. In oxidized cells, GLUT4 protein and mRNA levels were decreased, and a GLUT4 promoter segment containing the C/EBP binding site partially mediated oxidative stress-induced repression of a reported gene. The antioxidant lipoic acid protected against oxidation-induced decrease in GLUT4 and C/EBPalpha mRNA, but did not prevent the increase in C/EBPdelta mRNA. We propose that oxidative stress induces adipocyte insulin resistance partially by affecting the expression of C/EBPalpha and delta, resulting in altered C/EBP-dimer composition potentially occupying the GLUT4 promoter.     

Crystal structure of a novel viral protease with a serine/lysine catalytic dyad mechanism

The blotched snakehead virus (BSNV), an aquatic birnavirus, encodes a polyprotein (NH2-pVP2-X-VP4-VP3-COOH) that is processed through the proteolytic activity of its own protease (VP4) to liberate itself and the viral proteins pVP2, X and VP3. The protein pVP2 is further processed by VP4 to give rise to the capsid protein VP2 and four structural peptides. We report here the crystal structure of a VP4 protease from BSNV, which displays a catalytic serine/lysine dyad in its active site. This is the first crystal structure of a birnavirus protease and the first crystal structure of a viral protease that utilizes a lysine general base in its catalytic mechanism. The topology of the VP4 substrate binding site is consistent with the enzymes substrate specificity and a nucleophilic attack from the si-face of the substrates scissile bond. Despite low levels of sequence identity, VP4 shows similarities in its active site to other characterized Ser/Lys proteases such as signal peptidase, LexA protease and Lon protease. Together, the structure of VP4 provides insights into the mechanism of a recently characterized clan of serine proteases that utilize a lysine general base and reveals the structure of potential targets for antiviral therapy, especially for other related and economically important viruses, such as infectious bursal disease virus in poultry and infectious pancreatic necrosis virus in aquaculture.     

Glyphosate-induced anther indehiscence in cotton is partially temperature dependent and involves cytoskeleton and secondary wall modifications and auxin accumulation

Yield reduction caused by late application of glyphosate to glyphosate-resistant cotton (Gossypium hirsutum; GRC) expressing CP4 5-enol-pyruvylshikmate-3-P synthase under the cauliflower mosaic virus-35S promoter has been attributed to male sterility. This study was aimed to elucidate the factors and mechanisms involved in this phenomenon. Western and tissue-print blots demonstrated a reduced expression of the transgene in anthers of GRC compared to ovules of the same plants. Glyphosate application to GRC grown at a high temperature regime after the initiation of flower buds caused a complete loss of pollen viability and inhibition of anther dehiscence, while at a moderate temperature regime only 50% of the pollen grains were disrupted and anther dehiscence was normal. Glyphosate-damaged anthers exhibited a change in the deposition of the secondary cell wall thickenings (SWT) in the endothecium cells, from the normal longitudinal orientation to a transverse orientation, and hindered septum disintegration. These changes occurred only at the high temperature regime. The reorientation of SWT in GRC was accompanied by a similar change in microtubule orientation. A similar reorientation of microtubules was also observed in Arabidopsis (Arabidopsis thaliana) seedlings expressing green fluorescent protein tubulin (tubulin alpha 6) following glyphosate treatment. Glyphosate treatment induced the accumulation of high levels of indole-3-acetic acid in GRC anthers. Cotton plants treated with 2,4-dichlorophenoxyacetic acid had male sterile flowers, with SWT abnormalities in the endothecium layer similar to those observed in glyphosate-treated plants. Our data demonstrate that glyphosate inhibits anther dehiscence by inducing changes in the microtubule and cell wall organization in the endothecium cells, which are mediated by auxin.     

Image analysis for quantification of bacterial rock weathering

A fast, quantitative image analysis technique was developed to assess potential rock weathering by bacteria. The technique is based on reduction in the surface area of rock particles and counting the relative increase in the number of small particles in ground rock slurries. This was done by recording changes in ground rock samples with an electronic image analyzing process. The slurries were previously amended with three carbon sources, ground to a uniform particle size and incubated with rock weathering bacteria for 28 days. The technique was developed and tested, using two rock-weathering bacteria Pseudomonas putida R-20 and Azospirillum brasilense Cd on marble, granite, apatite, quartz, limestone, and volcanic rock as substrates. The image analyzer processed large number of particles (10(7)-10(8) per sample), so that the weathering capacity of bacteria can be detected.