Analysis of ECs and related compounds in plasma: artifactual isomerization and ex vivo enzymatic generation of 2-MGs

The analysis of peripheral endocannabinoids (ECs) is a good biomarker of the EC system. Their concentrations, from clinical studies, strongly depend on sample collection and time processing conditions taking place in clinical and laboratory settings. The analysis of 2-monoacylglycerols (MGs) (i.e., 2-arachidonoylglycerol or 2-oleoylglycerol) is a particularly challenging issue because of their ex vivo formation and chemical isomerization that occur after blood sample collection. We provide evidence that their ex vivo formation can be minimized by adding Orlistat, an enzymatic lipase inhibitor, to plasma. Taking into consideration the low cost of Orlistat, we recommend its addition to plasma collecting tubes while maintaining sample cold chain until storage. We have validated a method for the determination of the EC profile of a range of MGs and N-acylethanolamides in plasma that preserves the original isomer ratio of MGs. Nevertheless, the chemical isomerization of 2-MGs can only be avoided by an immediate processing and analysis of samples due to their instability during conservation. We believe that this new methodology can aid in the harmonization of the measurement of ECs and related compounds in clinical samples.     

Potential natural vegetation and pre‐anthropic pollen records on the Azores Islands in a Macaronesian context

This paper discusses the concept of potential natural vegetation (PNV) in the light of the pollen records available to date for the Macaronesian biogeographical region, with emphasis on the Azores Islands. The classical debate on the convenience or not of the PNV concept has been recently revived in the Canary Islands, where pollen records of pre‐anthropic vegetation seemed to strongly disagree with the existing PNV reconstructions. Contrastingly, more recent PNV model outputs from the Azores Islands show outstanding parallelisms with pre‐anthropic pollen records, at least in qualitative terms. We suggest the development of more detailed quantitative studies to compare these methodologies as an opportunity for improving the performance of both. PNV modelling may benefit by incorporating empirical data on past vegetation useful for calibration and validation purposes, whereas palynology may improve past reconstructions by minimizing interpretative biases linked to differential pollen production, dispersal and preservation.     

Deuterium-depleted water stimulates GLUT4 translocation in the presence of insulin,which leads to decreased blood glucose concentration

Molecular and Cellular Biochemistry - Deuterium (D) is a stable isotope of hydrogen (H) with a mass number of 2. It is present in natural waters in the form of HDO, at a concentration of...     

Dissociation of thrombin from platelets by hirudin. Evidence for receptor processing.

Hirudin inhibited the binding of human 125I-alpha-thrombin to the saturable, but not the nonsaturable, sites on washed human platelets. When hirudin was added to a thrombin-platelet mixture, it caused a biphasic dissociation of bound thrombin. A partial dissociation was too rapid to measure and was followed by complete dissociation with a first order rate constant of about 10(-2) s-1. The fraction of bound thrombin in the more slowly dissociable form increased from essentially none after a 5-s preincubation of thrombin and platelets to as much as 75% of saturable binding after a 4-min preincubation. Transition to the slowly dissociable state was not accompanied by an increase in the amount bound and was not observed with active site serine-derivatized thrombin. This is the first evidence with intact platelets of a binding characteristic that depends, as does platelet stimulation, on catalytically active thrombin, suggesting that it may represent physiologically significant receptor processing.     

The rose and the name: the unresolved debate on biotechnological terms

The largest survey on the perception of synthetic biology-related disciplines (Porcar et al., 2019,EMBO Rep 20) recently revealed that the Spanish society does not have a very positive perception of the term synthetic biology. On the other hand, the terms biotechnology and even genetic engineering received relatively higher scores. The issue of nomenclature and perception is a classical one in science perception studies. Synthetic biologists have been debating their neologism (Synthetic Biology, from now on SB) for years. Even in a 2006 blog, Rob Carlson discussed the various labels for the new field, such as intentional biology, constructive biology, natural engineering, synthetic genomics and biological engineering. This diversity of names, along with the above mentioned negative public perception of the term synthetic biology, raises the question on whether the term itself is suitable or whether it could, in an extreme scenario, be replaced by another combining scientific consensus with public acceptance.     

Effect of manganese(II) ion on trypsinogen activation

The effect of Mn²⁺ and Ca²⁺ on the kinetics of the tryptic activation of bovine trypsinogen was studied at pH 7.3 and 36.5°C. For comparison, the rate constants of autolysis and esterolytic activity of trypsin were also determined. It can be concluded that Mn²⁺ increases the conversion rate of trypsinogen into trypsin in a 25–40% larger extent than Ca²⁺. The manganese(II) ion bond to trypsinogen is supposed to keep the N-terminal part of the zymogen in a better conformation for binding at the primary and secondary binding sites of trypsin.