Controlling the interaction between CaMKII and Calmodulin with a photocrosslinking unnatural amino acid

Using unnatural amino acid mutagenesis, we made a mutant of CaMKII that forms a covalent linkage to Calmodulin upon illumination by UV light. Like wild-type CaMKII, the L308BzF mutant stoichiometrically binds to Calmodulin, in a calcium-dependent manner. Using this construct, we demonstrate that Calmodulin binding to CaMKII, even under these stochiometric conditions, does not perturb the CaMKII oligomeric state. Furthermore, we were able to achieve activation of CaMKII L308BzF by UV-induced binding of Calmodulin, which, once established, is further insensitive to calcium depletion. In addition to the canonical auto-inhibitory role of the regulatory segment, inter-subunit crosslinking in the absence of CaM indicates that kinase domains and regulatory segments are substantially mobile in basal conditions. Characterization of CaMKIIL308BzF in vitro, and its expression in mammalian cells, suggests it could be a promising candidate for control of CaMKII activity in mammalian cells with light

Smanjenje emisije drvne prašine tijekom piljenja drva univerzalnom kružnom pilom

The aim of this paper is a comparison of particle size distribution of sawdust in longitudinal sawing of wood by the universal circular saw when using two saw blades with different types of teeth. Experiments were carried out by use of a universal circular saw, at the cutting speed of v = 50 m·s-1 and feed speed of vf= 16 m·min-1. A universal saw blade with triangular asymmetric spring setting teeth K1 was used as a tool, as well as a saw blade with tipped swaged teeth K2. Specimens were used of spruce, beech and meranti wood with moisture content from 8 to 10%, species otherwise typical of the production of Euro windows. Granulometric analysis of produced sawdust was carried out by a sieve machine Fritch, with the set of sieves whose mesh gauge were as follows 1.0, 0.5, 0.355, 0.1, 0.05 and the bottom. Each specimen was meshed for 15 minutes and three specimens were meshed for each variant. The results show that larger chips were produced with the use of the saw blade K2 – the proportion of 1mm mesh, where the difference in using these two types of blades was up to 25% - meranti. From the viewpoint of airborne particles, it should be emphasised that with all three species of wood, the production of particles smaller than 100 micrometers (0.05 and bottom mesh) was twice lower when sawing was carried out with the saw blade K2 than with the saw blade K1. Even though the share of fine fraction was not considerable in the obtained samples, it can be stated that these amounts are also hazardous for the work environment and therefore attention should be drawn to the results of these experimental measurements, as it is possible to affect the proportion of fine fraction smaller than 100 micrometers by an adequate choice of tool.Cilj je provedenih istraživanja usporedba raspodjele veličina čestica usitnjenog materijala nastaloga longitudinalnim propiljivanjem drva kružnom pilom s dva lista različitog tipa zubi. Istraživanje je provedeno na univerzalnoj kružnoj pili pri brzini rezanja v = 50 m·s-1 i posmičnoj brzini vf = 16 m·min-1. Korišteni su listovi pile s asimetričnim trobridnim razvraćenim zubima K1 i sa stlačenim zubima K2. Odabrani su uzorci relativne vlažnosti od 8 do 10% od smrekovine, bukovine i merantija, drvnog materijala tipičnog za proizvodnju europrozora. Granulometrijska analiza uzoraka provedena je na tresilici proizvođača Fritch i sitima veličina (stranice kvadratnih otvora) 1,0; 0,5: 0,355; 0,1; 0,05 sa dnom. Svaki uzorak prosijavan je 15 minuta, uz tri ponavljanja. Rezultati pokazuju da pri piljenju listom pile K2 nastaju krupnije čestice te da je nastalo 25% više čestica merantija krupnijih od 1 mm nego pri piljenju listom pile K1. Za sve tri ispitivane vrste drva značajno je da nastane dvostruko manje čestica sitnijih od 100 mikrometara, tzv. lebdećih čestica (sito 0,05 s dnom) piljenjem pilom K2 negoli pilom K1. Iako dobiveni uzorci nisu sadržavali znatniji udio sitnih lebdećih čestica, zbog njihovoga štetnog utjecaja na zdravlje radnika, nužno je skrenuti pozornost na to da se odgovarajućim izborom alata može smanjiti udio drvnih čestica sitnijih od 100 mikrometara

Cuticular chemoprofile of the fruit fly Drosophila Subobscura (Diptera, drosophilidae)

In insects, cuticular hydrocarbon (CHC) profile is involved in many important biological functions and may vary in different conditions. Among fruit fly species, Drosophila subobscura is one of the most frequently used in genetic, ecological and evolutionary research, because of its rich chromosomal polymorphism, specific behavioral repertoires and habitat preferences. In this work, we identified and quantified cuticular chemoprofile of D. subobscura. Using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS), 25 chemical compounds were found in males and 23 compounds were found in females. Further, ANOVA confirmed significant sexual dimorphism in cuticular chemoprofile amounts. Knowledge of cuticular chemistry could contribute to further research in D. subobscura, starting from behavioral, up to ecological, since this species is recognized as an important model system for the study and monitoring of global climate changes. © 2018, Pakistan Agricultural Scientists Forum. All rights reserved

Cuticular chemoprofile of the fruit fly Drosophila Subobscura (Diptera, drosophilidae)

In insects, cuticular hydrocarbon (CHC) profile is involved in many important biological functions and may vary in different conditions. Among fruit fly species, Drosophila subobscura is one of the most frequently used in genetic, ecological and evolutionary research, because of its rich chromosomal polymorphism, specific behavioral repertoires and habitat preferences. In this work, we identified and quantified cuticular chemoprofile of D. subobscura. Using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS), 25 chemical compounds were found in males and 23 compounds were found in females. Further, ANOVA confirmed significant sexual dimorphism in cuticular chemoprofile amounts. Knowledge of cuticular chemistry could contribute to further research in D. subobscura, starting from behavioral, up to ecological, since this species is recognized as an important model system for the study and monitoring of global climate changes. © 2018, Pakistan Agricultural Scientists Forum. All rights reserved

Serial femtosecond zero dose crystallography captures a water‐free distal heme site in a dye‐decolourising peroxidase to reveal a catalytic role for an arginine in FeIV=O formation

Obtaining structures of intact redox states of metal centres derived from zero dose X‐ray crystallography can advance our mechanistic understanding of metalloenzymes. In dye‐decolourising heme peroxidases (DyPs), controversy exists regarding the mechanistic role of the distal heme residues, aspartate and arginine, in the heterolysis of peroxide to form the catalytic intermediate compound I (Fe IV =O and a porphyrin cation radical). Using serial femtosecond X‐ray (SFX) crystallography, we have determined the pristine structures of the Fe III and Fe IV =O redox states of a B‐type DyP. These structures reveal a water‐free distal heme site, which together with the presence of an asparagine, infer the use of the distal arginine as a catalytic base. A combination of mutagenesis and kinetic studies corroborate such a role. Our SFX approach thus provides unique insight into how the distal heme site of DyPs can be tuned to select aspartate or arginine for the rate enhancement of peroxide heterolysis