Evolutionary proteomics identifies amino acids essential for ligand-binding of the cytokinin receptor CHASE domain

Background  

In plants the hormone cytokinin is perceived by members of a small cytokinin receptor family, which are hybrid sensor histidine kinases. While the immediate downstream signaling pathway is well characterized, the domain of the receptor responsible for ligand binding and which residues are involved in this process has not been determined experimentally.     

Frasnian vertebrate taphonomy and sedimentology of macrofossil concentrations from the Langsēde Cliff,Latvia

Luk?evi?s, E., Ahlberg, P.E., Stinkulis, ?., Vasi?kova, J. & Zupi??, I. 2011: Frasnian vertebrate taphonomy and sedimentology of macrofossil concentrations from the Langsēde Cliff, Latvia. Lethaia, Vol. 45, pp. 356–370. The siliciclastic sequence of the Upper Devonian of Kurzeme, Western Latvia, is renowned for abundant vertebrate fossils, including the stem tetrapods Obruchevichthys gracilis and Ventastega curonica. During the first detailed taphonomic study of the vertebrate assemblage from the Ogre Formation cropping out at the Langsēde Cliff, Imula River, abundant vertebrate remains have been examined and identified as belonging to one psammosteid, two acanthodian and three sarcopterygian genera; the placoderm Bothriolepis maxima dominates the assemblage. Besides fully disarticulated placoderm and psammosteid plates, separate sarcopterygian scales and teeth, and acanthodian spines, partly articulated specimens including complete distal segments of Bothriolepis pectoral fins, Bothriolepis head shields and sarcopterygian lower jaws have been found. The size distribution of the placoderm bones demonstrates that the individuals within the assemblage are of approximately uniform age. Distinct zones have been traced within the horizontal distribution of the bones. These linear zones are almost perpendicular to the dominant dip azimuth of the cross‐beds and ripple‐laminae and most probably correspond to the depressions between subaqueous dunes. Concavity ratio varies significantly within the excavation area. The degree of fragmentation of the bones and disarticulation of the skeletons suggest that the carcasses were reworked and slightly transported before burial. Sedimentological data suggest deposition in a shallow marine environment under the influence of rapid currents. The fossiliferous bed consists of a basal bone conglomerate covered by a cross‐stratified sandstone with mud drapes, which is in turn overlain by ripple laminated sandstone, indicating the bones were buried by the gradual infilling of a tidal channel. All the Middle–Upper Devonian vertebrate bone‐beds from Latvia are associated with sandy to clayey deposits and have been formed in a sea‐coastal zone during rapid sedimentation episodes, but differ in fossil abundance and degree of preservation. □Agnathans, Devonian, facies analysis, fish, fossil assemblage, palaeoenvironment.     

Spiro-naphthyridinone piperidines as inhibitors of S. aureus and E. coli enoyl-ACP reductase (FabI)

Spiropiperidine naphthyridinone inhibitors of Staphylococcus aureus and Escherichia coli FabI have been prepared. Compounds 14a and 14c were identified as having sub-nanomolar E. coli FabI activity and are among the most potent FabI inhibitors yet described. The structural model of 14a bound to E. coli FabI is shown.     

A tree-based method for the rapid screening of chemical fingerprints

Background  

The fingerprint of a molecule is a bitstring based on its structure, constructed such that structurally similar molecules will have similar fingerprints. Molecular fingerprints can be used in an initial phase of drug development for identifying novel drug candidates by screening large databases for molecules with fingerprints similar to a query fingerprint.     

Recrafting the neighbor-joining method

Background  

The neighbor-joining method by Saitou and Nei is a widely used method for constructing phylogenetic trees. The formulation of the method gives rise to a canonical Θ(n ³) algorithm upon which all existing implementations are based.     

Current complex noninvasive diagnosis of parathyroid tumors

The diagnosis of bulky formations of the parathyroid glands (PTG) has become possible since current high-resolution techniques of visualization, such as ultrasound study (USS), computed tomography (CT), magnetic resonance imaging (MRI), were introduced into practice. The presence of clinical and/or laboratory signs of hyperparathyroidism (HPT) is a signal to initiate a goal-oriented search for abnormal PTG formations. The complex diagnosis of HPT involves the methods of detecting osteoporosis ranging from routine X-ray study of the hand and foot to more in-depth techniques: dichromatic X-ray absorptiometry (DXA) and quantitative CT (QCT). USS is an excellent method for screening if abnormal PTC changes are suspected; however, negative USS results in the presence of clinical and/or laboratory signs of HPT should not stop a diagnostic search. CT with intravenous contrast bolus specifies the site and structure of an formation, has some advantage in detecting retrosternal tumors. Due to its high tissue contrast, three-dimensional images, none ionizing radiation and osseous structural artefacts, MRI becomes a preferable tool for studying PTG when they are typically or atypically located. Needle biopsy is required when noninvasive methods cannot characterize the pattern of an abnormal PTG formation properly or their results are contradictory.     

Coculture of human endothelium and smooth muscle cells: functional heterogeneity of endothelial cells from zones with different susceptibility to atherosclerosis

Using co-culture technique and 3H-thymidine radioautography we have studied effects of human aortic endothelial cells (EC), isolated separately from zones of low (LP) and high (HP) probability of atherosclerosis of grossly normal and atherosclerotic aortas, on 3H-thymidine incorporation by human intimal smooth muscle cells (SMCs). It was found that EC activity depended on a zone of probability, from which the cells were isolated, and on the degree of atherosclerotic lesion. The first-passage ECs from grossly normal LP zones inhibited 3H-thymidine incorporation, compared to control, incubated without Ecs, SMCs (63.5 +/- 27.5%). Cells from HP zones of the same vessels were less active or stimulated SMC proliferation (99.4 +/- 42.9%). EC cultures obtained from both LP and HP zones of atherosclerotic vessels had, as a rule, no effect or increased 3H-thymidine incorporation by SMCs (100.3 +/- 19.8 and 124.1 +/- 20.1%). In contrast to morphologically heterogeneous primary and first-passage cultures obtained from high seeding density, EC monolayers obtained with a split 1:10 were composed predominantly of small mononuclear cells. These cultures effectively inhibited SMC DNA synthesis independently of a zone of probability and a degree of atherosclerotic lesion of aorta (60.4 +/- 10.0 and 51.5 +/- 12.7%). The obtained data suggest that EC morphological heterogeneity is accompanied by functional changes of cells and may be involved in atherosclerotic plaque formation.     

The NMR spin-echo method is used for measurements of the translational water diffusion selectively along the apoplast and the vacuolar and cytoplasmic symplasts of plant tissue

Simple methods for the registration of translational diffusion of water in apoplast and vacuolar and cytoplasmic symplasts were developed. The methods are based on spin-echo NMR with a pulsed magnetic field gradient and are realized by preliminary inversion of magnetization and the use of paramagnetic doping. It was shown that the diffusion of a part of root water in segments of mais roots is more enhanced than that for the bulk water. The results are explained by the appearance of the rotational movement of the protoplasm and in terms of the hypothesis of water transfer along the apoplast, which balances the cytoplasmic symplast.