Acetylcholinesterase Inhibitory Activity of Modified Lupane,Oleanane, and Ursane A-seco-Triterpenoids

A series of new lupane, ursane, and oleanane type triterpenic A-seco-derivatives containing bromo-, azido-, alkyne-, 1H-tetrazol-5-yl-, 5-methyloxazol-2-yl-, N-(4-(4-methylpiperazin-1-yl)but-2-yn-1-yl), and a carbonyl group at C2, C24, C28, C30 positions has been synthesized. The bioactivity was evaluated by Ellman's method, and the results showed that most of the compounds displayed moderate acetylcholinesterase inhibitory activities in vitro. Among them, A-seco-derivatives of 28-oxo-allobetuline and betulinic acid with bromo- and azido-groups exhibited the most potent inhibitory activity against AChE. Extra experiments showed methyl 2-cyano-3,4-seco-dibromo- and 2-cyano-3,4-seco-diazido-derivatives of betulinic acid as mixed-type inhibitors, with Ki values as low as K_i=0.18 μM and K_i=0.21 μM, respectively.     

Animal evolution during domestication: the domesticated fox as a model

We review the evolution of domestic animals, emphasizing the effect of the earliest steps of domestication on its course. Using the first domesticated species, the dog (Canis familiaris), for illustration, we describe the evolutionary peculiarities during the historical domestication, such as the high level and wide range of diversity. We suggest that the process of earliest domestication via unconscious and later conscious selection of human‐defined behavioral traits may accelerate phenotypic variations. The review is based on the results of a long‐term experiment designed to reproduce early mammalian domestication in the silver fox (Vulpes vulpes) selected for tameability or amenability to domestication. We describe changes in behavior, morphology and physiology that appeared in the fox during its selection for tameability, which were similar to those observed in the domestic dog. Based on the data of the fox experiment and survey of relevant data, we discuss the developmental, genetic and possible molecular genetic mechanisms underlying these changes. We ascribe the causative role in evolutionary transformation of domestic animals to the selection for behavior and to the neurospecific regulatory genes it affects.     

Agr2‐interacting Prod1‐like protein Tfp4 from Xenopus laevis is necessary for early forebrain and eye development as well as for the tadpole appendage regeneration

The Agr family genes, Ag1, Agr2, and Agr3, encode for the thioredoxin domain containing secreted proteins and are specific only for vertebrates. These proteins are attracting increasing attention due to their involvement in many physiological and pathological processes, including exocrine secretion, cancer, regeneration of the body appendages, and the early brain development. At the same time, the mode by which Agrs regulate intracellular processes are poorly understood. Despite that the receptor to Agr2, the membrane anchored protein Prod1, has been firstly discovered in Urodeles, and it has been shown to interact with Agr2 in the regenerating limb, no functional homologs of Prod1 were identified in other vertebrates. This raises the question of the mechanisms by which Agrs can regulate regeneration in other lower vertebrates. Recently, we have identified that Tfp4 (three‐fingers Protein 4), the structural and functional homolog of Prod1 in Anurans, interacts with Agr2 in Xenopus laevis embryos. In the present work we show by several methods that the activity of Tfp4 is essential for the tadpole tail regeneration as well as for the early eye and forebrain development during embryogenesis. These data show for the first time the common molecular mechanism of regeneration regulation in amphibians by interaction of Prod1 and Agr2 proteins.     

Biosurfactant-enhanced immobilization of hydrocarbon-oxidizing Rhodococcus ruber on sawdust

Immobilization of microorganisms on/in insoluble carriers is widely used to stabilize functional activity of microbial cells in industrial biotechnology. We immobilized Rhodococcus ruber, an important hydrocarbon degrader, on biosurfactant-coated sawdust. A biosurfactant produced by R. ruber in the presence of liquid hydrocarbons was found to enhance rhodococcal adhesion to solid surfaces, and thus, it was used as a hydrophobizing agent to improve bacterial attachment to a sawdust carrier. Compared to previously used hydrophobizers (drying oil and n-hexadecane) and emulsifiers (methyl- and carboxymethyl cellulose, poly(vinyl alcohol), and Tween 80), Rhodococcus biosurfactant produced more stable and homogenous coatings on wood surfaces, thus resulting in higher sawdust affinity to hydrocarbons, uniform monolayer distribution of immobilized R. ruber cells (immobilization yield 29–30 mg dry cells/g), and twofold increase in hydrocarbon biooxidation rates compared to free rhodococcal cells. Two physical methods, i.e., high-resolution profilometry and infrared thermography, were applied to examine wood surface characteristics and distribution of immobilized R. ruber cells. Sawdust-immobilized R. ruber can be used as an efficient biocatalyst for hydrocarbon transformation and degradation.     

Enhanced-contrast two-photon optogenetic pH sensing and pH-resolved brain imaging

We present experiments on cell cultures and brain slices that demonstrate two-photon optogenetic pH sensing and pH-resolved brain imaging using a laser driver whose spectrum is carefully tailored to provide the maximum contrast of a ratiometric two-photon fluorescence readout from a high-brightness genetically encoded yellow-fluorescent-protein-based sensor, SypHer3s. Two spectrally isolated components of this laser field are set to induce two-photon-excited fluorescence (2PEF) by driving SypHer3s through one of two excitation pathways—via either the protonated or deprotonated states of its chromophore. With the spectrum of the laser field accurately adjusted for a maximum contrast of these two 2PEF signals, the ratio of their intensities is shown to provide a remarkably broad dynamic range for pH measurements, enabling high-contrast optogenetic deep-brain pH sensing and pH-resolved 2PEF imaging within a vast class of biological systems, ranging from cell cultures to the living brain.