Plant phylogeny drives arboreal caterpillar assemblages across the Holarctic

1. Assemblages of insect herbivores are structured by plant traits such as nutrient content, secondary metabolites, physical traits, and phenology. Many of these traits are phylogenetically conserved, implying a decrease in trait similarity with increasing phylogenetic distance of the host plant taxa. Thus, a metric of phylogenetic distances and relationships can be considered a proxy for phylogenetically conserved plant traits and used to predict variation in herbivorous insect assemblages among co‐occurring plant species.
2. Using a Holarctic dataset of exposed‐feeding and shelter‐building caterpillars, we aimed at showing how phylogenetic relationships among host plants explain compositional changes and characteristics of herbivore assemblages.
3. Our plant–caterpillar network data derived from plot‐based samplings at three different continents included >28,000 individual caterpillar–plant interactions. We tested whether increasing phylogenetic distance of the host plants leads to a decrease in caterpillar assemblage overlap. We further investigated to what degree phylogenetic isolation of a host tree species within the local community explains abundance, density, richness, and mean specialization of its associated caterpillar assemblage.
4. The overlap of caterpillar assemblages decreased with increasing phylogenetic distance among the host tree species. Phylogenetic isolation of a host plant within the local plant community was correlated with lower richness and mean specialization of the associated caterpillar assemblages. Phylogenetic isolation had no effect on caterpillar abundance or density. The effects of plant phylogeny were consistent across exposed‐feeding and shelter‐building caterpillars.
5. Our study reveals that distance metrics obtained from host plant phylogeny are useful predictors to explain compositional turnover among hosts and host‐specific variations in richness and mean specialization of associated insect herbivore assemblages in temperate broadleaf forests. As phylogenetic information of plant communities is becoming increasingly available, further large‐scale studies are needed to investigate to what degree plant phylogeny structures herbivore assemblages in other biomes and ecosystems.

     

The spinal cord supports of vertebrae in the crown‐group salamanders (Caudata,Urodela)

The development of spinal cord supports (bony thickenings which extend into the vertebral canal of vertebrae) in primitive (Salamandrella keyserlingii) and derived (Lissotriton vulgaris) salamanders were described. The spinal cord supports develop as the protuberances of periostal bone of the neural arches in the anteroproximal part of the septal collagenous fibers which connect a transverse myoseptum with the notochord and spinal cord, in the septal bundle inside the vertebral canal. Spinal cord supports were also found in some teleostean (Salmo salar, Oncorhynchus mykiss) and dipnoan (Protopterus sp.) fishes. The absence of the spinal cord supports in vertebrates with cartilaginous vertebrae (lampreys, chondrichthyan, and chondrostean fishes) corresponds to the fact that the spinal cord supports are bone structures. The absence of the spinal cord supports in frogs correlates with the lack of the well developed septal bundles inside the vertebral canal. The spinal cord supports are, presumably, a synapomorphic character for salamanders which originated independently of those observed in teleostean and dipnoan fishes. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

A determination key to the structural types of seattered green using the air multispectral photography

Scattered green was studied in Czechoslovakia by means of the air multispectral photography and of the field observation. According to various repartition and canopy 19 structural types of seattered green were derived.     

Peptides and multiple antigen peptides from Schistosoma mansoni glyceraldehyde 3-phosphate dehydrogenase: preparation, immunogenicity and immunoprotective capacity in C57BL/6 mice.

Four monoepitopic MAPs (MAP A, B, C and E) and one bis-diepitopic MAP B-E derived fromthe primary sequence of Schistosoma mansoni glyceraldehyde 3-phosphate dehydrogenase, previously tested in BALB/c mice, were examined for their immunogenicity and protective capacity in C57BL/6 mice. Despite multimerization into MAPs, MAP Aand MAP C were poorly immunogenic. In contrast toBALB/c mice, MAP E was non-immunogenic in C57BL/6 mice. Peptide B in the form of MAP B orbis-diepitopic MAPB-E elicited immune responses in C57BL/6 mice that were associated with a significant decrease in worm burden. The MAPs were prepared by the stepwise solid-phase peptide synthesis using Boc/Bzl chemistry, successfully purified on the RP-HPLC column and characterized by RP-HPLC, HPCE and MALDI-TOF MS techniques. A general strategy for MAPs purification is discussed here and the purification of MAP Band MAP E is documented in detail.     

Effectiveness of acylation of protein amino groups with fatty acid chlorides in a system of reversed micelles of aerosol OT in octane

The characteristics of water-soluble enzyme (alpha-chymotrypsin) modification with [3H] palmitoyl chloride in the reversed Aerosol OT micelles in octane were determined. The degree of enzyme modification depends on the molar ratio [palmitoyl chloride]/[protein]. The modification reaction is characterized by the wide pH-optimum range and proceeds with high speed.     

A new strategy for the study of oligomeric enzymes: gamma-glutamyltransferase in reversed micelles of surfactants in organic solvents

A heterodimeric enzyme (gamma-glutamyltransferase) was studied in the reversed micellar medium of Aerosol OT (AOT) in octane. As was shown earlier, the size (radius) of inner cavity of the AOT-reversed micelles is determined by their hydration degree, i.e., [H2O]/[AOT] molar ratio, in the system. Owing to this, the dependence of hydrolytic, transpeptidation and autotranspeptidation activities of the enzyme on the hydration degree was investigated using L- and D-isomers of gamma-glutamyl(3-carboxy-4-nitro)anilide and glycylglycine as substrates. For all of the reaction types, the observed dependences are curves with three optima. The optima are found at the hydration degrees, [H2O]/[AOT] = 11, 17 and 26 when the inner cavity radii of reversed micelles are equal to the size of light (Mr 21,000) and heavy (Mr 54,000) subunits of gamma-glutamyltransferase, and to their dimer (Mr 75,000), respectively. Ultracentrifugation experiments showed that a change of the hydration degree resulted in a reversible dissociation of the enzyme to light and heavy subunits. The separation of light and heavy subunits of gamma-glutamyltransferase formed in reversed micelles was carried out and their catalytic properties were studied. The two subunits catalyze hydrolysis and transpeptidation reactions; autotranspeptidation reaction is detected only in the case of the heavy subunit. These findings imply that the reversed micelles of surfactants in organic solvents function as the matrices with adjustable size permitting to regulate the supramolecular structure and the catalytic activity of oligomeric enzymes.     

A new way in homogeneous immunoassay: reversed micellar systems as a medium for analysis

Possibilities of a new principle for the homogeneous enzyme immunoassay utilizing the systems of surfactant reversed micelles in organic solvents have been demonstrated taking thyroxine determination as an example. The catalytic activity of an enzyme, solubilized in such systems, is determined by the ratio of geometric dimensions of the micellar matrice and the enzyme molecule. The addition of antibodies against thyroxine to the peroxidase-thyroxine conjugate, solubilized in the system of reversed micelles of aerosol OT in octane, leads to the formation of the immune complex whose size differs substantially from that of the initial enzyme-antigen conjugate. This induces changes in the peroxidase catalytic activity. The addition of free thyroxine to the system stimulates the conjugate release from the immune complex and, consequently, the reduction of the peroxidase activity to the initial level. Sensitivity of the analysis in reversed micellar systems can be regulated by changing the surfactant hydration degree. Substances of different nature (both hydrophobic and hydrophylic) can be solubilized in reverse micellar systems under standard conditions, which allows determination of water insoluble antigens.     

Artificial oligomerization of enzymes--a new way of regulating their catalytic activity in reversed micellar systems]

Comparative studies were carried out in the catalytic activity regulation of native alpha-chymotrypsin and its artificially produced hexameric form as an example of non-dissociating oligomeric enzyme (covalently cross-linked by means of succinimidyl-3-(2-pyridylthiopropionate] in the Aerosol OT reversed micelles in octane. Native (monomeric) alpha-chymotrypsin exhibits maximal catalytic activity in the reversed micelles at the hydration degree w0 = 10, when the radius of the micelle inner cavity is equal to the radius of the alpha-chymotrypsin globule. For the alpha-chymotrypsin hexamer, optimum is observed at w0 = 45, with the inner micellar cavity radius (r = 68 A) being approximately equal to the radius of the sphere surrounding the octahedral combination of the six monomeric alpha-chymotrypsin molecules (r = 61 A). Thus, construction of the corresponding oligomeric structures is made easy, with the optimal catalytic activity in a preset range of the hydration degrees.     

Enhancement of chloroplast energization in Chlorella by treatments inactivating the nitrate-reducing system

Inactivation of the nitrate-reducing system in whole cells of Chlorella vulgaris Bejerinck by darkening, nitrogen starvation, ammonium, or cycloheximide brings cells into a state with a high yield of the millisecond-delayed fluorescence of chlorophyll. Activation of this system by illumination, by adding glucose to dark-adapted cells or nitrate to nitrogen-starved cells brings the cells into a low-yield state. The transitions between the lowand high-yield state induced by alternating light and dark periods are suppressed by tungstate and restored by subsequent molybdate addition. The drop in the delayed-fluorescence yield upon activation of the nitrate-reducing system is associated with the decrease of the amplitude of the electrochemical proton gradient across the thylakoid membrane of the chloroplast, as evidenced by the kinetics of the light-induced adsorption changes at 520 nm. The decrease of the proton gradient may be caused by the electron flow diverting from the cyclic path in photosystem I as a result of the activation of the electron transfer from ferredoxin to nitrite.Abbreviation DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea