Space-related research in mycology concurrent with the first decade of manned space exploration

Fungi and Actinomycetes, aside from other microorganisms, have been placed aboard balloons, earth satellites, or high altitude sounding rockets for evaluation of environmental conditions of spaceflight missions. The incursion of harmful effects, including chromosomal breaks or elevated mutation frequencies were identified.     

Lanthanide-based fluorogenic peptide substrate for the highly sensitive detection of thermolysin

A new fluorogenic, lanthanide-based oligopeptide substrate for the detection of the zinc-dependent endoprotease thermolysin is described. Using time-resolved fluorescence measurement, a highly sensitive assay for thermolysin was developed with a 50 pM detection limit (3.5 fmol).     

Glycogen Shunt Activity and Glycolytic Supercompensation in Astrocytes May Be Distinctly Mediated via the Muscle Form of Glycogen Phosphorylase

Glycogen is the main storage form of glucose in the brain. In contrast with previous beliefs, brain glycogen has recently been shown to play important roles in several brain functions. A fraction of metabolized glucose molecules are being shunted through glycogen before reentering the glycolytic pathway, a phenomenon known as the glycogen shunt. The significance of glycogen in astrocyte energetics is underlined by high activity of the glycogen shunt and the finding that inhibition of glycogen degradation, under some conditions leads to a disproportional increase in glycolytic activity, so-called glycolytic supercompensation. Glycogen phosphorylase, the key enzyme in glycogen degradation, is expressed in two different isoforms in brain, the muscle and the brain isoform. Recent studies have illustrated how these are differently regulated. In the present study, we investigate the role of the two isoforms in glycolytic supercompensation in cultured astrocytes with the expression of either one of the isoforms silenced by siRNA knockdown. When reintroducing glucose to glucose-starved astrocytes, glycolytic activity increased dramatically. Interestingly, the increase was 30% higher in astrocytes not expressing the muscle isoform of glycogen phosphorylase. Based on these results and previously published data we couple the muscle isoform of glycogen phosphorylase to glycolytic supercompensation and glycogen shunt activity, giving insights to the underlying mechanistic of these phenomena.     

Ten microsatellite loci for the strawberry poison frog (Oophaga pumilio)

We describe primers and PCR conditions to amplify nine new tetranucleotide loci and one new dinucleotide locus isolated from the strawberry poison frog (Oophaga pumilio). In 21 individuals from Costa Rica, the number of alleles ranged from 4 to 16, observed heterozygosities from 40 to 100%, and polymorphic information content ranged from 0.60 to 0.90 per locus. Evidence for linkage disequilibrium was found only between two loci, but this pattern was not found in other populations tested. All primer pairs cross-amplified in Oophaga vicentei from Panama.     

Characterization of recombinant human acetyl-CoA carboxylase-2 steady-state kinetics

Acetyl-CoA carboxylase (ACC) catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, a key metabolite in the fatty acid synthetic and oxidation pathways. The present study describes the steady-state kinetic analysis of a purified recombinant human form of the enzyme, namely ACC2, using a novel LC/MS/MS assay to directly measure malonyl-CoA formation. Four dimensional matrices, in which bicarbonate (HCO₃^?), ATP, acetyl-CoA, and citrate were varied, and global data fitting to appropriate steady-state equations were used to generate kinetic constants. Product inhibition studies support the notion that the enzyme proceeds through a hybrid (two-site) random Ter Ter mechanism, one that likely involves a two-step reaction at the biotin carboxylase domain. Citrate, a known activator of animal forms of ACC, activates both by increasing k_cat and k_cat/K_M for ATP and acetyl-CoA.     

Imaging of fatty tumors: appearance of subcutaneous lipomas in optoacoustic images

A wide variety of subcutaneous soft‐tissue masses may be seen in clinical practice. Clinical examination based on palpation alone is often insufficient to identify the nature and exact origin of the mass, in which case imaging is necessary. We used handheld multispectral optoacoustic imaging technology (MSOT) in a proof‐of‐principle study to image superficial fatty tumors and compare the images with diagnostic ultrasound. Fatty tumors were clearly visualized by MSOT and exhibited a spectral signature which differed from normal fatty tissue or muscle tissue. Our findings further indicated that MSOT offers highly complementary contrast to sonography. Based on the performance achieved, we foresee a promising role for MSOT in the diagnosis and evaluation of subcutaneous soft‐tissue masses. Picture : Pseudo‐color representation of a cross‐sectional multi‐spectral optoacoustic slice through a subcutaneous lipoma. Multi‐spectral information is encoded in color. The lipoma can clearly be distinguished from the surrounding tissue based on its color. Scalebar 1 cm.     

Characterization of zinc amino acid complexes for zinc delivery in vitro using Caco-2 cells and enterocytes from hiPSC

Zn is essential for growth and development. The bioavailability of Zn is affected by several factors such as other food components. It is therefore of interest, to understand uptake mechanisms of Zn delivering compounds to identify ways to bypass the inhibitory effects of these factors. Here, we studied the effect of Zn amino acid conjugates (ZnAAs) on the bioavailabilty of Zn. We used Caco-2 cells and enterocytes differentiated from human induced pluripotent stem cells from a control and Acrodermatitis enteropathica (AE) patient, and performed fluorescence based assays, protein biochemistry and atomic absorption spectrometry to characterize cellular uptake and absorption of ZnAAs. The results show that ZnAAs are taken up by AA transporters, leading to an intracellular enrichment of Zn mostly uninhibited by Zn uptake antagonists. Enterocytes from AE patients were unable to gain significant Zn through exposure to ZnCl₂ but did not show differences with respect to ZnAAs. We conclude that ZnAAs may possess an advantage over classical Zn supplements such as Zn salts, as they may be able to increase bioavailability of Zn, and may be more efficient in patients with AE.     

Lipid biomarkers, pigments and cyanobacterial diversity of microbial mats across intertidal flats of the arid coast of the Arabian Gulf (Abu Dhabi, UAE)

Variations in morphology, fatty acids, pigments and cyanobacterial community composition were studied in microbial mats across intertidal flats of the arid Arabian Gulf coast. These mats experience combined extreme conditions of salinity, temperature, UV radiation and desiccation depending on their tidal position. Different mat forms were observed depending on the topology of the coast and location. The mats contained 63 fatty acids in different proportions. The increased amounts of unsaturated fatty acids (12–39%) and the trans/cis ratio (0.6–1.6%) of the cyanobacterial fatty acid n- 18:1ω9 in the higher tidal mats suggested an adaptation of the mat microorganisms to environmental stress. Chlorophyll a concentrations suggested lower cyanobacterial abundance in the higher than in the lower intertidal mats. Scytonemin concentrations were dependent on the increase in solar irradiation, salinity and desiccation. The mats showed richness in cyanobacterial species, with Microcoleus chthonoplastes and Lyngbya aestuarii morphotypes as the dominant cyanobacteria. Denaturing gradient gel electrophoresis patterns suggested shifts in the cyanobacterial community dependent on drainage efficiency and salinity from lower to higher tidal zones. We conclude that the topology of the coast and the variable extreme environmental conditions across the tidal flat determine the distribution of microbial mats as well as the presence or absence of different microorganisms.     

Novel imidazo[1,2-a]pyrazine derivatives as potent reversible inhibitors of the gastric H+/K+-ATPase

A series of novel 6-substituted imidazo[1,2-a]pyrazines were synthesized via palladium catalyzed amino- or alkoxycarbonylation as key step. The anti-secretory activity of these compounds has been assessed in a binding assay against H(+)/K(+)-ATPase from hog gastric mucosa. Some of the compounds proved to be potent inhibitors of the gastric acid pump.