On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.     

The use of batumin-containing disks for the rapid identification of staphylococci

The study of 467 microbial strains obtained from collections and from clinical sources revealed that microorganisms of the genus Staphylococcus were highly sensitive to batumin, a new antibiotic obtained from bacteria of the genus Pseudomonas. 378 strains of 15 Staphylococcus species proved to be highly sensitive to the diagnostic preparation "Diastaph", developed on the basis of batumin (antibiotic-impregnated discs); After 18-hour incubation the diameter of the growth inhibition zones on agar-containing culture media was 18-38 mm. Strains belonging to the genera Micrococcus, Dermacoccus, Kocuria and Kytococcus, as well as the tested representatives of other taxa (Planococcus, Streptococcus, Corynebacterium, Acinetobacter, Pseudomonas, Neisseria, the representatives of all tested genera of the family Enterobacteriaceae, fungi of the genus Candida) were insensitive to the diagnosticum. "Diastaph" permits not only the rapid identification of staphylococci pure cultures, but also the determination of their presence in association with other microbial species directly in pathological material, which makes it possible to recommend this diagnostic preparation for use in medical, veterinary and sanitary microbiology.     

Genetic basis of influenza virus virulence: gene composition and virulence of reassortants between mouse-adapted and nonadapted strains from different subtypes

Reassortment analysis of the pneumovirulence for mice marker of influenza virus has been performed. The original A/USSR/90/77 (H1H1) influenza virus strain or its mouse-adapted variant were crossed with a variant of A/Aichi/2/68 (H3N2) influenza virus highly virulent for mice. The reassortant having HA gene of the original A/USSR/90/77 virus and the other genes of the highly virulent A/Aichi/2/68 strain was avirulent for mice, whereas a similar reassortant possessing HA gene of the mouse-adapted A/USSR/90/77 strain was as virulent as A/Aichi/2/68 parent virus. The reasortant having HA and M genes of A/Aichi/2/68 and other genes of the mouse-adapted A/USSR/90/77 was moderately virulent, resembling in this respect the latter parent. The data indicates that changes in the different genes in course of viral adaptation to mice result in a differential acquisition of virulence for mice.     

Species loss of stoneflies (Plecoptera) in the Czech Republic during the 20th century

1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955–1960 and 2006–2010. Historical data (1890–1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large‐scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near‐natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area.     

An N-terminal, 830 residues intrinsically disordered region of the cytoskeleton-regulatory protein supervillin contains Myosin II- and F-actin-binding sites

Supervillin, the largest member of the villin/gelsolin family, is a cytoskeleton regulating, peripheral membrane protein. Supervillin increases cell motility and promotes invasive activity in tumors. Major cytoskeletal interactors, including filamentous actin and myosin II, bind within the unique supervillin amino terminus, amino acids 1–830. The structural features of this key region of the supervillin polypeptide are unknown. Here, we utilize circular dichroism and bioinformatics sequence analysis to demonstrate that the N-terminal part of supervillin forms an extended intrinsically disordered region (IDR). Our combined data indicate that the N-terminus of human and bovine supervillin sequences (positions 1–830) represents an IDR, which is the largest IDR known to date in the villin/gelsolin family. Moreover, this result suggests a potentially novel mechanism of regulation of myosin II and F-actin via the intrinsically disordered N-terminal region of hub protein supervillin.     

Compounds similar to acyclovir. III. Synthesis of acyclic analogs of 5'-deoxynucleosides

A convenient method has been proposed for the synthesis of 1,2-dihydroxy-4-oxahex-3-yl and 1-hydroxy-4-oxahex-3-yl derivatives of guanine, adenine, thymine and cytosine, acyclic nucleoside analogues lacking the 3'--4' bond.     

Mechanism of effect of extracellular pH on L-type Ca(2+) channel currents in human mesenteric arterial cells

Extracellular pH (pH(o)) influences vasoconstriction partly by modulating Ca(2+) influx through voltage-gated Ca(2+) channels in the vasculature. The mechanism of this effect of pH(o) is, however, controversial. Using the whole cell voltage-clamp technique, we examined the influence of pH(o) on L-type Ca(2+) channel currents in isolated human mesenteric arterial myocytes. Acidification to pH 6.2 and alkalinization to 8.2 from 7.2 decreased by approximately 50% and increased by 25-30%, respectively, the peak amplitude of Ca(2+) and Ba(2+) currents (1.5 and 10 mM), with an apparent pK(a) of 6.8. Activation and inactivation of Ca(2+) and Ba(2+) currents were shifted toward positive membrane voltages during acidification and in the opposite direction during alkalinization. The relationship between the current amplitude and shifts in the gating parameters in solutions of different pH(o) conformed closely to that predicted by the Gouy-Chapman model, in which the divalent cation concentration at the outer surface of the membrane varies with the extent to which protons neutralize the membrane surface potential.     

Incorporation of the ampicillin resistance transposon into the Escherichia coli K-12 chromosome and into plasmids]

The mutant pEG1 of R-factor RP4 with temperature-sensitive defect in replication, carrying a transposable ampicillin resistance element Tn1 was used to define the frequency of insertion of this element into Escherichia coli K-12 chromosome and some other plasmids. Our results indicate that the frequency of colony forming by bacteria with pEG1-factor on ampicillin medium in non-permissive conditions corresponds to the frequency of Tn1 insertion into bacterial chromosome or some other plasmid (in case when the strains are carrying a second plasmid). The frequency of Tn1 insertion into the chromosome is about 4.10(-4). The defect in recA gene produce no serious change in the frequency of Tn1 insertion into the bacterial chromosome. The translocation of Tn1 element from pEG1-factor to R483, R6 and ColE1 plasmids occurs at 10 to 100-fold-higher frequency than from the plasmid to the chromosome. The insertion of Tn1 into the F'-factor KLF10 and R-factor R64-11 occurs at far lower frequency than that to plasmids R6, R483, or ColE1.     

Identification of smooth muscle-derived foam cells in the atherosclerotic plaque of human aorta with monoclonal antibody IIG10

We have developed a monoclonal antibody that specifically interacts with a surface antigen of human fibroblasts and smooth muscle cells. The antibody (antibody IIG10) recognizes a polypeptide of molecular mass 330,000, revealed by immunoblotting in fibroblast and smooth muscle cell extract, but not in vascular endothelial cells, peritoneal macrophages, peripheral blood lymphocytes nor hepatocytes. In tissue sections the antibody stained smooth muscle cells of myometrium, aorta and smaller blood vessels, and fibroblasts of connective tissue. Specificity of the antibody was further confirmed by double staining of aorta sections. Antibody IIG10 was used to identify smooth muscle-derived foam cells in the atherosclerotic plaque of human aorta.     

Characterization of commercial laminin preparations from human placenta in comparison to recombinant laminins 2 (alpha2beta1gamma1), 8 (alpha4beta1gamma1), 10 (alpha5beta1gamma1).

Laminins, a family of large heterotrimeric (alphabetagamma) proteins, are major components of basement membranes implicated in a variety of cellular functions. Different commercial laminin preparations isolated from human placenta have been widely used in functional studies but their molecular properties are poorly known. In the present study, we characterized several of these preparations by ELISA, silver staining and Western blotting, in comparison to mouse laminin 1 (alpha1beta1gamma1), and recombinant human laminins 2 (alpha2beta1gamma1), 8 (alpha4beta1gamma1) and 10 (alpha5beta1gamma1). The cell migration-promoting activity of different batches was also tested. The placenta laminin preparations differed from one another and consisted of highly fragmented proteins, a mixture of laminin isoforms, and/or contaminating fibronectin. Major functional differences between batches were also observed, reflecting molecular heterogeneity. Previous data obtained in functional studies using these preparations need to be interpreted with caution and may require revision, and future functional studies demand prior molecular characterization of the laminins, particularly their alpha-chain.