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.     

Surface-active properties of antibiotics

The critical concentrations of the mycella formation of novobiocin, mithramycin, variamycin, erythromycin, oleandomycin and lincomycin were determined with two methods by changes in the isotherms of the surface tension and in the maximum absorption of rodamine due to the antibiotic concentrations. The results obtained with the two methods were comparable.     

The NAD-Booster Nicotinamide Riboside Potently Stimulates Hematopoiesis through Increased Mitochondrial Clearance

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Chimeric Virus as a Source of the Potato Leafroll Virus Antigen

Large quantities of potato leafroll virus (PLRV) antigen are difficult to obtain because this virus accumulates in plants at a low titer. To overcome this problem, we constructed a binary vector containing chimeric cDNA, in which the coat protein (CP) gene of the crucifer infecting tobacco mosaic virus (crTMV) was substituted for the coat protein gene of PLRV. The PLRV movement protein (MP) gene, which overlaps completely with the CP gene, was doubly mutated to eliminate priming of the PLRV MP translation from ATG codons with no changes to the amino acid sequence of the CP. The untranslated long intergenic region located upstream of the CP gene was removed from the construct. Transcribed powerful tobamovirus polymerase of the produced vector synthesized PLRV CP gene that was, in turn, translated into the protein. CP PLRV packed RNAs from the helical crTMV in spherical virions. Morphology, size and antigenic specificities of the wild-type and chimeric virus were similar. The yield of isolated chimera was about three orders higher than the yield of native PLRV. The genetic manipulations facilitated the generation of antibodies against the chimeric virus, which recognize the wild-type PLRV.     

Nisin adsorption on silica adsorbents

It has been shown that silica adsorbents can be used for adsorption of nizin from solutions obtained after centrifugation of the fermentation broth. The optimal structure of the adsorbent pores has been determined. Silica with pores 50 to 75 nm in size provided the highest adsorption rates. The value of silica adsorption of nizin depended on the medium pH. The maximum adsorption rates were observed at pH 6.5--7. At pH 3.5 the level of nizin adsorption was low.     

Human Discrimination of the Angular Velocity of the Vertical Movement of an Acoustic Image in Opposite Directions

The discrimination of the angular velocity of ventrodorsal and dorsoventral movement of an acoustic image was studied in nine test subjects. The experiments were performed using an apparent movement produced by consecutive activation of loudspeakers located along an arc in the vertical plane. The differential thresholds were measured by the minimum increment method. As the velocity of an acoustic image movement in opposite directions increased, the values of its mean absolute differential thresholds increased monotonically. Regression lines plotted by linear approximation of these values did not differ significantly.     

Control of the human and animal locomotor activity in the absence of supraspinal effects

In patients deprived of supraspinal effects, electrical epidural stimulation of the spinal cord's dorsal surface at the level of 2nd lumbar segment induces step-like movements accompanied by respective electromyographic activity of the leg's muscles. Triggering of the step-like movements occurs at certain parameters of the stimulation. The data obtained suggest that human spinal cord has networks of interneurons-generators of the step-like movements. A leading role of the spinal cord's propriospinal system in activation of spinal generators of stepping under epidural influences was shown in cats.