Cholinesterase hydrolysis of acetylcholine derivatives with different structures of the ammonium grouping]

15 acetoxyethylenammonium compounds are studied as substrates for acetylcholinesterase (ACE) from bovine erythrocytes and for butyrylcholinesterase (BCE) from horse serum. Substitution of methyl groups of the ammonium grouping with other radicals and incorporation of onium nitrogen in the cycle resulted in the decrease of the hydrolysis rate under the action of BCE and ACE, the effect of BCE being more pronounced. The rate of the hydrolysis of N-acetoxyethylene-N-methylpiperidine iodide in the presence of ACE was 65 times as much as in the presence of BCE. This compound is a new specific substrate of ACE. Dipropylmethyl derivative turned not to be a good substrate for both enzymes. Dibutylmethyl and pyridinic derivatives were not attacked by ACE and BCE. Kinetic analysis of the compounds listed is performed, taking account of non-productive sorbtion. Possible role of hydrofobic regions in the orientation of substrates on the active surface of ACE and BCE is discussed.     

Vulnerability of birds to contaminated water sources in the Karoo region of South Africa

The Karoo is a unique region in South Africa in terms of its ecological processes and endemic species. Large areas are needed to maintain viable populations of nomadic birds that follow erratic rainfall events and subsequent food and nesting resources, as well as ephemeral standing water. Whereas many species are adapted to arid conditions, our trait-based analysis found that an unusually large percentage (almost 45%) of 315 bird species in the semi-arid Karoo region rely on water to some degree. Indeed, some birds may have benefited from human activities to date, such as through the provision of water for livestock. However, this reliance on water makes birds vulnerable to changes in water quality stemming from various industrial developments. Given the large areas of the Karoo under consideration for concessions, the most noteworthy of these is hydraulic fracturing for shale gas, which results in a large quantity of waste water (‘produced water’) that contains a wide variety of chemicals, including petroleum byproducts. Given the negative impacts of secondary waste water on wildlife in other parts of the world where shale-gas exploration is being undertaken, careful attention must be given to preventing access to such produced water by an estimated 60 to 141 species of birds that make use of the water in the Karoo.     

Circulating stromal osteonectin-positive progenitor cells and stenotic coronary atherosclerosis

The level of circulating stromal progenitor cells carrying osteonectin (ON), a marker of osteogenic differentiation, was evaluated by flow cytometry in blood of patients with coronary artery disease (CAD). Ninety-nine patients with CAD were included into the study. Coronary angiography of all patients showed critical stenosis of at least 2 coronary arteries or their major branches. The control groups included 8 patients without CAD and 19 healthy volunteers. In control patients, no lesions of the coronary bed were found by angiography. The absence of CAD in the volunteers was confirmed by bicycle stress test. The content of ON-positive cells in blood was examined in various populations of lymphocyte-like cells. It was found that the number of ON+ lymphocyte-like cells with CD41 positivity in blood of patients without coronary stenosis (0.27%+/-0.11%, mean+/-SD) did not differ significantly from corresponding value in healthy volunteers (0.26%+/-0.07%, p=0.94). In CAD patients, the percent of these ON+ cells was 1.01%+/-0.49% and was significantly higher than in blood of healthy volunteers (p<0.0001) and patients without CAD (p<0.0001). High content of ON+ lymphocyte-like cells with CD41 positivity in blood may serve as noninvasive marker of arterial atherosclerosis.     

Morphofunctional characteristics of the conjunctival microcirculation of students of different regions of the world

By means of vital microscopy, the conjunctival microcirculation has been estimated in students from various regions of the world depending on duration of the time of their life in the USSR. Adaptive rearrangements of the conjunctival microcirculation of the eye ball have been revealed in various time of adaptation. Integral estimation of the conjunctival microcirculation has demonstrated that at initial phase of adaptation synchronization in the work of separate links of the microcirculatory bed is observed. These changes can be interpreted as strain of the compensatory mechanisms. In two years of study, certain stabilization of the microcirculation system activity is observed in the foreign students; this can be considered as the phase of stable adaptation. In the students arrived from hot regions of the world, pigmentation in the eye ball conjunctiva has been revealed. By means of the correlative analysis it has been demonstrated that the pigmentation influences the most labile parts of the microcirculatory bed-capillaries and venules. Pigmentation is usually regarded as a pathological sign peculiar for some diseases. Our investigations have demonstrated that pigmentation should be interpreted carefully and the place of residence of the students investigated should be taken into account, since pigmentation can be the result of elevated solar radiation, specific for hot regions of the Earth.     

Population structure of the Japanese eel, Anguilla japonica

Mitochondrial DNA (mtDNA) sequences that include (a) a part of the cytochrome b gene, (b) two tRNA genes, and (c) a part of the noncoding D-loop region of 31 Anguilla japonica (Japanese eel) and 1 A. marmorata collected from Taiwan, Japan, and mainland China were determined to evaluate the population structure of Japanese eel. Among 30 genotypes identified from the 31 Japanese eel mtDNAs sequenced, there are 58 variable sites, predominantly clustered at the D-loop region. The phylogenetic tree constructed by the unweighted pair-group method with arithmetic mean shows neither significant genealogical branches nor geographic clusters. Furthermore, the sequence-statistics test reveals little, if any, significant genetic differentiation. These results indicate that the 31 Japanese eels might come from a single population. Analysis of sequence variation in mtDNA by using the relationship between the number of segregating sites and the average number of nucleotide differences under the neutral mutation hypothesis reveals that neutral mutation acts as a major factor influencing the evolutionary divergence of the Japanese eel mitochondrial genome sequenced, especially in the noncoding region.      

Molecular evolution of P transposable elements in the genus Drosophila. I. The saltans and willistoni species groups

A phylogenetic survey using the polymerase chain reaction (PCR) has identified four major P element subfamilies in the saltans and willistoni species groups of Drosophila. One subfamily, containing about half of the sequences studied, consists of elements that are very similar to the canonical (and active) P element from D. melanogaster. Within this subfamily, nucleotide sequence differentiation among different copies from the same species and among elements from different species is relatively low. This observation suggests that the canonical elements are relatively recent additions to the genome or, less likely, are evolving slowly relative to the other subfamilies. Elements belonging to the three noncanonical lineages are distinct from the canonical elements and from one another. Furthermore, there is considerably more sequence variation, on the average, within the noncanonical subfamilies compared to the canonical elements. Horizontal transfer and the coexistence of multiple, independently evolving element subfamilies in the same genome may explain the distribution of P elements in the saltans and willistoni species groups. Such explanations are not mutually exclusive, and each may be involved to varying degrees in the maintenance of P elements in natural populations of Drosophila.      

An enzyme immunoassay system for aflatoxin B1

Indirect enzyme immunoassay based on immobilized conjugate of aflatoxin B₁ carboxymethyloxime with bovine serum albumin and polyclonal rabbit antibodies allows determining aflatoxin B₁ with a low relative cross-reactivity against aflatoxin B₂, G₁, G₂, M₁ B_2a, and G_2a and sterigmatocystin (15.5, 15.5, 1.7, 1.0, 0.03, 0.03 and 0.01%, respectively) with a sensitivity of 0.04 ng per well or 4.0 ng per ml organic solvent.