Design of novel analogues of short antimicrobial peptide anoplin with improved antimicrobial activity

Currently, novel antibiotics are urgently required to combat the emergence of drug‐resistant bacteria. Antimicrobial peptides with membrane‐lytic mechanism of action have attracted considerable interest. Anoplin, a natural α‐helical amphiphilic antimicrobial peptide, is an ideal research template because of its short sequence. In this study, we designed and synthesized a group of analogues of anoplin. Among these analogues, anoplin‐4 composed of d ‐amino acids displayed the highest antimicrobial activity due to increased charge, hydrophobicity and amphiphilicity. Gratifyingly, anoplin‐4 showed low toxicity to host cells, indicating high bacterial selectivity. Furthermore, the mortality rate of mice infected with Escherichia coli was significantly reduced by anoplin‐4 treatment relative to anoplin. In conclusion, anoplin‐4 is a novel anoplin analogue with high antimicrobial activity and enzymatic stability, which may represent a potent agent for the treatment of infection. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

Salvaging Pyrococcus furiosus Protein Targets at SECSG

Proteins derived from the coding regions of Pyrococcus furiosus are targets for three-dimensional X-ray and NMR structure determination by the Southeast Collaboratory for Structural Genomics (SECSG). Of the 2200 open reading frames (ORFs) in this organism, 220 protein targets were cloned and expressed in a high-throughput (HT) recombinant system for crystallographic studies. However, only 96 of the expressed proteins could be crystallized and, of these, only 15 have led to structures. To address this issue, SECSG has recently developed a two-tier approach to protein production and crystallization. In this approach, tier-1 efforts are focused on producing protein for new Pfu(italics?) targets using a high-throughput approach. Tier-2 protein production efforts support tier-1 activities by (1) producing additional protein for further crystallization trials, (2) producing modified protein (further purification, methylation, tag removal, selenium labeling, etc) as required and (3) serving as a salvaging pathway for failed tier-1 proteins. In a recent study using this two-tiered approach, nine structures were determined from a set of 50 Pfu proteins, which failed to produce crystals suitable for X-ray diffraction analysis. These results validate this approach and suggest that it has application to other HT crystal structure determination applications.     

Climatic signals in tree ring of Picea schrenkiana along an altitudinal gradient in the central Tianshan Mountains, northwestern China

Tree-ring samples of Picea schrenkiana (Fisch. et Mey) were studied along an altitudinal gradient in the central Tianshan Mountains, and ring-width chronologies were developed for three sites at different altitudes: low-forest border (1600–1700 m a.s.l.), interior forest (2100–2200 m a.s.l.), and upper treeline (2600–2700 m a.s.l.). Annual ring-width variations were similar among the three sites but variability was greatest at the low-forest border site. The statistical characters of the chronologies showed that mean sensitivity (MS) and standard deviation (SD) decreased with increasing elevation. In other words, the response of tree growth to environmental changes decreased with increasing altitude. To understand the differing response of trees at different elevations to the environmental changes, response function analysis was used to study the relationships between tree-ring widths and mean monthly temperature and total monthly precipitation from 1961 to 2000. The results showed that precipitation was the most important factor limiting tree radial growth in the arid central Tianshan Mountains, precipitation in August of the prior growth year played an important role on tree's radial growth across the entire altitudinal gradient even at the cold, high-elevation treeline site. It is expected that with increasing altitude air temperature decreased and precipitation increased, the importance of precipitation on tree growth decreased, and the response of tree growth to environmental changes decreased, too. This conclusion may be helpful to understand and research the relationship between climatic change and tree growth in arid and semiarid area.     

The Postnatal Development of the Cerebellum— A fMRI and Silver Study

Summary The aim of this study was to evaluate the postnatal development of the cerebella of the pig and to compare this with the activation of the fMRI. The cells in the cerebella were studied by silver technique and the activation of the fMRI in the cerebella was initiated by flexion and extension of the hind paw. Our results showed an increase of the branching of the cells of the cerebellar cortex postnatally, coordinated with registration of fMRI active sites in the cerebella at 6-month postnatal. We concluded that the full maturation of the cerebella was around 6-month postnatal in the pig.     

Enzymatic esterification between n-alcohol homologs and n-caprylic acid in non-aqueous medium under microwave irradiation

The enzymatic esterification between n-alcohol homologs and n-caprylic acid catalyzed by lipozyme RM IM (LRI) in microwave field was investigated. Some interesting findings were obtained. The optimum reaction temperature slightly shifted from that in enzymatic esterification by conventional heating. n-Alcohol homologs used in this experiment showed substrate specificity in terms of the odd and even carbon numbers. THF expressed abnormal solvent effect. Whereas in the contrastive enzymatic esterification by conventional heating, the above mentioned substrate specificity and solvent effect were not observed. All the above phenomena could be explained by both thermal and non-thermal effect of microwave on enzyme and substrates. Further investigation revealed that microwave irradiation reduced the apparent activation energy of the enzymatic reaction according to Arrhenius equation, which is considered as one of the causes increasing initial reaction rate.     

R-ISSR as a new tool for genomic fingerprinting, mapping, and gene tagging

In the present study we propose and test the concept of R-ISSR, a new tool for genomic fingerprinting, mapping, and gene tagging. The concept is based on the fact that primers for inter-simple sequence repeat (ISSR) and random-amplified polymorphic DNA (RAPD) analysis elicit different genomic information, and the combined use of these 2 kinds of primers in the same polymerase chain reaction (PCR) reactions might reveal new genomic loci that could not be detected with either technique alone. The feasibility of this tool was first electronically simulated with sequence analysis software andArabidopsis chromosome sequence. Next, different combinations of ISSR and RAPD primers were applied in real PCR reactions to detect new genomic loci in 2 maize lines (Q319 and 1145). Sequencing gels were used to separate PCR products and showed good resolving ability in comparison with agarose gels. RAPD primers could be successfully used with ISSR primers for the detection of new genomic loci and applied in a new way for genomic mapping, fingerprinting, and gene tagging.     

Substituted aminobenzimidazole pyrimidines as cyclin-dependent kinase inhibitors

A series of aminobenzimidazole-substituted pyrimidines were synthesized and evaluated for biochemical activity against CDK1. A high-speed parallel synthesis approach enabled the identification of a potent lead series having improved potency in the CDK1 assay (IC(50)<10nM). Cell cycle analysis showed that the compounds induced a G2/M block. Docking studies were carried out with a CDK1 homology model, and provide a rationale for the observed activities.     

Effects of paeoniflorin on the cerebral infarction, behavioral and cognitive impairments at the chronic stage of transient middle cerebral artery occlusion in rats

In the present study, the effects of paeoniflorin (PF), a characteristic monoterpene glucoside isolated from Paeoniae Radix, on cerebral infarction, neurological symptoms, tongue protrusion (TP) and performance in the water maze were examined at the chronic stage (4 weeks) of transient cerebral ischemia using a rat middle cerebral artery occlusion (MCAO) model. One-day (10 mg/kg, twice, s.c.) or seven-day (2.5-10 mg/kg, twice a day, s.c.) injection of PF significantly reduced the infarct volume as well as ameliorated the deficits in neurological symptoms caused by transient MCAO at chronic stage. Transient MCAO also induced impairments in TP and performance in the water maze. Treatment with PF was able to reverse or alleviate these impairments. These results indicate that PF may be effective for treatment of stroke.     

Design, synthesis, and bioavailability evaluation of coumarin-based prodrug of meptazinol

Based on the known coumarin-based prodrug system, a new meptazinol (Z)-3-[2-(propionyloxy) phenyl]-2-propenoic ester (3) was designed and synthesized as prodrug to minimize the first-pass effect of meptazinol (1) and improve the oral bioavailability. The prodrug (3) showed a 4-fold increase in oral bioavailability over the parent drug meptazinol in rats.     

Characterization and crystallization of human DPY-30-like protein, an essential component of dosage compensation complex

Human DPY-30-like is a homolog of C. elegans DPY-30. DPY-30 is an essential component of dosage compensation machinery and loss of dpy-30 activity results in XX-specific lethality. In XO animals, DPY-30 is required for developmental processes other than dosage compensation. In yeast, the homolog of DPY-30, Saf19p, functions as a member of histone 3 lysine 4 methylation complex, which is the key part of epigenetic developmental control. In this report, human DPY-30-like protein was overexpressed and purified with the goal of structure determination. It was crystallized at 291 K in hanging drops by the vapour diffusion technique from a precipitant solution consisting of (NH4)2SO4 (1.5-2.0 M), Tris-HCl (0.1 M, pH 8.0). The crystal diffracted to 2.7 A resolution at 100 K in-house and belongs to the space group P4(1)2(1)2 or P4(3)2(1)2 with unit-cell parameters of a=b=74.5 A, c=87.0 A, alpha=beta=gamma=90.0 degrees. The asymmetric unit contains two molecules with 49% solvent content. We also analyzed its biochemical and biophysical characterizations. Efforts are now under way to determine the molecular structure of the DPY-30-like. These studies will open a new avenue towards the structure-based functional analysis of human DPY-30-like and dosage compensation machinery.