Perturbation of the molecular clockwork in the SCN of non-obese diabetic mice prior to diabetes onset

Circadian disruption is associated with the development of diabetes. Non-obese diabetic (NOD) mice show abnormal diurnal profiles in energy balance and locomotor activity suggesting circadian misalignment. Therefore, we analyzed cFos and mPER1 as markers for rhythmic neuronal activity within the suprachiasmatic nucleus (SCN) of wildtype (WT) and non-diabetic (nNOD) as well as acutely diabetic NOD (dNOD) mice. cFos levels show a day/night difference in both WT and nNOD but not in dNOD. mPER1 levels did not show a day/night difference in both nNOD and dNOD. This suggests that disruption of SCN rhythmicity in NOD mice precedes the actual onset of diabetes.     

Lignocellulosic biomass: Biosynthesis,degradation, and industrial utilization

Lignocellulose biomass derived from plant cell walls is a rich source of biopolymers, chemicals, and sugars, besides being a sustainable alternative to petrochemicals. A natural armor protecting living protoplasts, the cell wall is currently the target of intense study because of its crucial importance in plant development, morphogenesis, and resistance to (a)biotic stresses. Beyond the intrinsic relevance related to the overall plant physiology, plant cell walls constitute an exquisite example of a natural composite material that is a constant source of inspiration for biotechnology, biofuel, and biomaterial industries. The aim of the present review is to provide the reader with an overview of the current knowledge concerning lignocellulosic biomass synthesis and degradation, by focusing on its three principal constituents, i.e. cellulose, hemicellulose (in particular xylan), and lignin. Furthermore, the current industrial exploitation of lignocellulose from fast growing fibre crops (such as hemp) is highlighted. We conclude this review by suggesting approaches for further research to fill gaps in our current knowledge and to highlight the potential of biotechnology and bioengineering in improving both biomass biosynthesis and degradation.     

Pilot Preclinical and Clinical Evaluation of (4S)-4-(3-[18F]Fluoropropyl)-L-Glutamate (18F-FSPG) for PET/CT Imaging of Intracranial Malignancies

Purpose

(S)-4-(3-[¹⁸F]Fluoropropyl)-L-glutamic acid (18F-FSPG) is a novel radiopharmaceutical for Positron Emission Tomography (PET) imaging. It is a glutamate analogue that can be used to measure x_C^- transporter activity. This study was performed to assess the feasibility of 18F-FSPG for imaging orthotopic brain tumors in small animals and the translation of this approach in human subjects with intracranial malignancies.

Experimental Design

For the small animal study, GS9L glioblastoma cells were implanted into brains of Fischer rats and studied with 18F-FSPG, the 18F-labeled glucose derivative 18F-FDG and with the 18F-labeled amino acid derivative 18F-FET. For the human study, five subjects with either primary or metastatic brain cancer were recruited (mean age 50.4 years). After injection of 300 MBq of 18F-FSPG, 3 whole-body PET/Computed Tomography (CT) scans were obtained and safety parameters were measured. The three subjects with brain metastases also had an 18F-FDG PET/CT scan. Quantitative and qualitative comparison of the scans was performed to assess kinetics, biodistribution, and relative efficacy of the tracers.

Results

In the small animals, the orthotopic brain tumors were visualized well with 18F-FSPG. The high tumor uptake of 18F-FSPG in the GS9L model and the absence of background signal led to good tumor visualization with high contrast (tumor/brain ratio: 32.7). 18F-FDG and 18F-FET showed T/B ratios of 1.7 and 2.8, respectively. In the human pilot study, 18F-FSPG was well tolerated and there was similar distribution in all patients. All malignant lesions were positive with 18F-FSPG except for one low-grade primary brain tumor. In the 18F-FSPG-PET-positive tumors a similar T/B ratio was observed as in the animal model.

Conclusions

18F-FSPG is a novel PET radiopharmaceutical that demonstrates good uptake in both small animal and human studies of intracranial malignancies. Future studies on larger numbers of subjects and a wider array of brain tumors are planned.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01186601","term_id":"NCT01186601"}}NCT01186601     

Structural analysis of prokaryotic and eukaryotic 5S rRNAs by RNase H

The availabilities of single-stranded 5S rRNA regions c, d and d' for base pairing interactions were analyzed by using synthetic DNA oligomers. Hybrid formation was detected by the endonucleolytical mode of the RNA-DNA specific action of RNase H. Provided that the hybrid interaction involved 6 successive base pairs, 5S rRNA loop c nucleotides 42-47 displayed accessibility in Escherichia coli, Bacillus stearothermophilus and Thermus thermophilus 5S rRNAs as well as in eukaryotic 5S rRNAs from Saccharomyces carlsbergensis, Rattus rattus and Equisetum arvense. Investigating eubacterial 5S rRNA regions d and d' (nucleotides 71-76 and 99-105, respectively), susceptibility was observed in E. coli 5S rRNA which, however, decreases in B. stearothermophilus and even more so in T. thermophilus 5S rRNA. For additional evaluation of the data obtained by RNase H cleavage, association constants of the hexanucleotides were determined by equilibrium dialysis at 4 degrees C for B. stearothermophilus 5S rRNA. The results obtained reveal that nucleotides 36-41 of B. stearothermophilus 5S rRNA are inaccessible for Watson-Crick interaction, which suggests that this part of loop c is in a structurally constrained configuration, or buried in the tertiary structure or involved in tertiary interactions.     

Deoxyribonucleic acid reassociation and interspecies relationships of the genusChlorella (Chlorophyceae)

Phylogenetic relationships within the genusChlorella were studied by means of DNA/DNA hybridization under both optimal and relaxed reassociation conditions as well as by determination of the thermal stability of hybrid DNA duplexes. The results indicate a relationship betweenC. fusca var.fusca, C. fusca var.rubescens, C. fusca var.vacuolata, and the genusScenedesmus. In addition, the strains endosymbiotic withParamecium bursaria seem to be related with theC. vulgaris/sorokiniana group. The relations between most other species, however, could not be sufficiently resolved by the above methods. This implies considerable phylogenetic divergency within the genusChlorella.     

Cyanobacterial glutamate 1-semialdehyde aminotransferase: requirement for pyridoxamine phosphate

Glutamate 1-semialdehyde aminotransferase has been separated from metabolically related activities by gel filtration and affinity chromatography. The enzyme was inhibited by gabaculin, 4-amino 5-fluoropentanoic acid and pyridoxal 5-phosphate and stimulated by pyridoxamine 5-phosphate. The activity of enzyme recovered by elution after electrophoresis in non-denaturing polyacrylamide gels was wholly dependent on pyridoxamine 5-phosphate. A mechanism for the enzyme-catalysed reaction based on these observations is discussed.Abbreviations AFPA 4-amino 5-fluoropentanoic acid - ALA -aminolaevulinic acid - DTT dithiothreitol - GSA glutamate 1-semialdehyde - PAL-P pyridoxal 5-phosphate - PAM-P pyridoxamine 5-phosphate - PCC Paris Culture Collection