The morphology of mouthparts,wings and genitalia of Paleozoic insect families Protohymenidae and Scytohymenidae reveals new details and supposed function

Megasecoptera is an extinct group of insects with specialized rostrum-like mouthparts, which is a synapomorphy shared with all members of the Late Paleozoic Palaeodictyopterida, and markedly slender wings that are unable to flex backwards. Here we describe the close up morphology of Protohymenidae and Scytohymenidae and uncover new aspects of the endoskeleton (tentorium) of the head, structure of the mouthparts with discernible proximal part of stylets controlled by muscles, surface of compound eyes that consist of a hexagonal pattern of large facets, structure and microstructures on the wings and reconstruct male and female external genitalia using ESEM and light stereomicroscopy. Furthermore, we describe Protohymen novokshonovi sp. n. based on an exceptionally well preserved fossil from the early Permian at Tshekarda in Russia, which shows crucial details, and the earliest species of Protohymenidae, Carbohymen testai gen. et sp. n. from a late Carboniferous siderite nodule at Mazon Creek in Illinois, USA. Our comparative study confirmed a set of structural and microstructural details on their wings, such as the composite anterior wing margin, development of an apical cell and the previously unknown external genitalia. Based on the results and comparison of homologous structures known primarily for extant relatives, such as mayflies and dragonflies, we outline for the first time the function of the mouthparts, in particular, the stylets, structure of the tentorium, vision provided by large hexagonal ommatidia and male copulatory structures bearing curved claspers for holding a female during copulation and penial lobes with seminal grooves.     

Dummy birds in artificial nest studies: an experiment with Red-backed Shrike Lanius collurio

Capsule Dummy birds placed on artificial nests increase nest survival, and their use should be considered in future studies of nest predation.     

Cultivar-specific kinetics of chitinase induction in soybean roots during exposure to arsenic

The kinetics of defense responses was studied in soybean exposed to ecologically relevant concentrations of arsenic for 96 h. In the roots of two soybean cultivars with contrasting tolerance to this metalloid there were observed differences in basal levels of membrane lipid peroxidation as well as a significantly different course of peroxidation upon exposure to As. The different course of stress was reflected in the accumulation of defense components. The responses of individual chitinase isoforms were studied since these enzymes had previously been shown to be stable components of defense against metals. The kinetics and magnitude of accumulation of the three isoforms during exposure to As significantly differed within as well as between the studied cultivars. Furthermore, accumulation of these isoforms appeared to be related to oxidative status in the root tissue. The timing of induced responses is likely to be important for efficient defense against metal(oid) pollution in environment.     

Discovery of the genus Crinoedischia in the Middle Permian of France (Insecta: Orthoptera)

New orthopteran Crinoedischia lapeyriei sp. nov. is described and illustrated from the Middle Permian (Guadalupian) of Lodève Basin in southern France. The new species is separated from the Lower Permian (Artinskian) Crinoedischia species by differences in wing venation pattern such as long ScP with anterior branches, RA with prominent distal branches, and MA ending with three branches. The significance and parallels of entomofaunas between Salagou and Wellington formations (Lodève, Elmo, Midco) are briefly discussed.     

Conformational Transitions of Poly(dl-dC) in Aqueous Solution as Studied by Ultraviolet Resonance Raman Spectroscopy

Abstract

Poly(dI-dC) in aqueous solution can undergo different equilibrium geometries, which strongly depend on salt nature and concentrations. These equilibrium structures have been monitored by resonance Raman spectroscopy (RRS) measurements in the ultraviolet region, i. e. by using 257 and 281 nm laser excitation wavelengths which favor the resonance enhancement of the Raman contributions from inosine and cytosine residues of poly(dI-dC), respectively. Spectral changes depending on the NaCl concentration and on the presence of Ni²⁺ ions have been observed and interpreted in comparison with RRS results previously obtained for other alternating purine-pyrimidine polydeoxyribonucleotides, i.e. poly(dG-dC), poly(dA- dT) and poly(dA-dC). poly(dG-dT), which also showed B to Z conformational transitions in varying the salt concentrations. It is shown here that: i) the base stacking geometries are nearly the same in the high-salt form (5 M NaCl) of poly(dl-dC) as in the low-salt form (0.1M NaCl) of the polymer, ii) however, the high-salt structure yields important differences from a B-helix (obtained in low-salt solution) as regards the nucleoside conformations (sugar puckering and base-sugar orientation), and: iii) the addition of 9 mM NiCl₂ in the high-salt (5 M NaCl) solution of poly(dI-dC) induces the Z-conformation of the polymer.     

Functional Impairment of Microglia Coincides with Beta-Amyloid Deposition in Mice with Alzheimer-Like Pathology

Microglial cells closely interact with senile plaques in Alzheimer’s disease and acquire the morphological appearance of an activated phenotype. The significance of this microglial phenotype and the impact of microglia for disease progression have remained controversial. To uncover and characterize putative changes in the functionality of microglia during Alzheimer’s disease, we directly assessed microglial behavior in two mouse models of Alzheimer’s disease. Using in vivo two-photon microscopy and acute brain slice preparations, we found that important microglial functions - directed process motility and phagocytic activity - were strongly impaired in mice with Alzheimer’s disease-like pathology compared to age-matched non-transgenic animals. Notably, impairment of microglial function temporally and spatially correlated with Aβ plaque deposition, and phagocytic capacity of microglia could be restored by interventionally decreasing amyloid burden by Aβ vaccination. These data suggest that major microglial functions progressively decline in Alzheimer’s disease with the appearance of Aβ plaques, and that this functional impairment is reversible by lowering Aβ burden, e.g. by means of Aβ vaccination.     

Degradation of beta-hexachlorocyclohexane by haloalkane dehalogenase LinB from gamma-hexachlorocyclohexane-utilizing bacterium Sphingobium sp. MI1205

The technical formulation of hexachlorocyclohexane (HCH) mainly consists of the insecticidal γ-isomer and noninsecticidal α-, β-, and δ-isomers, among which β-HCH is the most recalcitrant and has caused serious environmental problems. A γ-HCH-utilizing bacterial strain, Sphingobium sp. MI1205, was isolated from soil which had been contaminated with HCH isomers. This strain degraded β-HCH more rapidly than the well-characterized γ-HCH-utilizing strain Sphingobium japonicum UT26. In MI1205, β-HCH was converted to 2,3,5,6-tetrachlorocyclohexane-1,4-diol (TCDL) via 2,3,4,5,6-pentachlorocyclohexanol (PCHL). A haloalkane dehalogenase LinB (LinB_MI) that is 98% identical (seven amino-acid differences among 296 amino acids) to LinB from UT26 (LinB_UT) was identified as an enzyme responsible for the two-step conversion of β-HCH to TCDL. This property of LinB_MI contrasted with that of LinB_UT, which catalyzed only the first step conversion of β-HCH to PCHL. Site-directed mutagenesis and computer modeling suggested that two of the seven different amino acid residues (V134 and H247) forming a catalytic pocket of LinB are important for the binding of PCHL in an orientation suitable for the reaction in LinB_MI. However, mutagenesis also indicated the involvement of other residues for the activity unique to LinB_MI. Sequence analysis revealed that MI1205 possesses the IS6100-flanked cluster that contains two copies of the linB _MI gene. This cluster is identical to the one located on the exogenously isolated plasmid pLB1, suggesting that MI1205 had recruited the linB genes by a horizontal transfer event.     

The structural diversity of DNA–neutral phospholipids–divalent metal cations aggregates: a small-angle synchrotron X-ray diffraction study

We investigate the structure of aggregates formed due to DNA interaction with saturated neutral phosphatidylcholines [dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine] in presence of Ca²⁺ and Mg²⁺ cations using simultaneous synchrotron small- and wide-angle X-ray diffractions. For DPPC:DNA = 3:1 mol/base and in the range of 1–50 mM Ca²⁺, the diffractograms show structural heterogeneity of aggregates. We observe the coexistence of two lamellar phases in aggregates prepared at 1 mM Ca²⁺: L^x phase with the DNA strands (of unknown organization) intercalated in water layers between adjacent lipid bilayers and L_DPPC phase of DPPC bilayers without any divalent cations and DNA strands. Aggregates prepared in the range 2–50 mM Ca²⁺ show a condensed gel lamellar phase L_g^c with the lipid bilayer periodicity d ≈ 8.0 nm, and the DNA–DNA interhelical distance d _DNA ≈ 5.1 nm. The increase of temperature induces the decrease in the intensity and the increase in the width of the DNA related peak. In the fluid state, the condensed lamellar phase L_α^c gradually converts into L^x phase. The aggregates do not exhibit rippled P_β phase. The thermal behaviour of aggregates was investigated in the range 20–80°C. Applying heating–cooling cycles, the aggregates converted into energetically more favourable structure: a condensed lamellar phase L^c (or L^x) is preserved or we observe lateral segregation of the DNA strands and metal cations (L^x phase) in coexistence with L_PC phase of pure phospholipids. Dedicated to Prof. Dr Klaus Arnold on the occasion of his 65th birthday.     

Bioanalytical strategy used in development of pharmacokinetic (PK) methods that support biosimilar programs

The development of biosimilar products is expected to grow rapidly over the next five years as a large number of approved biologics reach patent expiry. The pathway to regulatory approval requires that similarity of the biosimilar to the reference product be demonstrated through physiochemical and structural characterization, as well as within in vivo studies that compare the safety and efficacy profiles of the products. To support nonclinical and clinical studies pharmacokinetic (PK) assays are required to measure the biosimilar and reference products with comparable precision and accuracy. The most optimal approach is to develop a single PK assay, using a single analytical standard, for quantitative measurement of the biosimilar and reference products in serum matrix. Use of a single PK assay for quantification of multiple products requires a scientifically sound testing strategy to evaluate bioanalytical comparability of the test products within the method, and provide a solid data package to support the conclusions. To meet these objectives, a comprehensive approach with scientific rigor was applied to the development and characterization of PK assays that are used in support of biosimilar programs. Herein we describe the bioanalytical strategy and testing paradigm that has been used across several programs to determine bioanalytical comparability of the biosimilar and reference products. Data from one program is presented, with statistical results demonstrating the biosimilar and reference products were bioanalytically equivalent within the method. The cumulative work has established a framework for future biosimilar PK assay development.     

The Heleochloëtum alopecuroidis association in the Pannonian Basin — fiction or reality?

The understanding of some plant communities can often be ambiguous if studies from multiple countries are considered, because goals and methods in each country may differ. The presented work is based on a detailed review of historic and recent literature about the association Heleochloëtum alopecuroidis in the Pannonian Basin and tangentially the adjacent regions within Central and SE Europe compared to authors’ field data. The named community was generally reported in moderately saline and marshy habitats in lowland areas, nevertheless it is not documented by phytosociological relevés to be part of the halophytic alliance of Cypero-Spergularion salinae. We performed a critical assessment of stands with the species Heleochloa alopecuroides in halophytic vegetation where we added our own data from field research between 2003 and 2013 (1044 phytosociological relevés) and 354 unpublished and published relevés taken from the three National Phytosociological Databases (Czech Republic, Hungary, Slovakia).We conclude that association Heleochloëtum alopecuroidis cannot be properly described as being part of the Pannonian halophytic vegetation group. It should be therefore deleted from the vegetation surveys.