Harpalus hospes ciscaucasicus Lutshn. (Coleoptera,Carabidae), a Ground Beetle Subspecies with a Widely Disjunctive Geographical Range

Entomological Review - Harpalus hospes Sturm, 1818 is a predominantly Eastern Mediterranean species with three parapatric subspecies connected by the populations with intermediate characteristics...     

A SNP-based genetic dissection of versatile traits in bread wheat (Triticum aestivum L.)

The continuous increase in global population prompts increased wheat production. Future wheat (Triticum aestivum L.) breeding will heavily rely on dissecting molecular and genetic bases of wheat yield and related traits which is possible through the discovery of quantitative trait loci (QTLs) in constructed populations, such as recombinant inbred lines (RILs). Here, we present an evaluation of 92 RILs in a bi-parental RIL mapping population (the International Triticeae Mapping Initiative Mapping Population [ITMI/MP]) using newly generated phenotypic data in 3-year experiments (2015), older phenotypic data (1997–2009), and newly created single nucleotide polymorphism (SNP) marker data based on 92 of the original RILs to search for novel and stable QTLs. Our analyses of more than 15 unique traits observed in multiple experiments included analyses of 46 traits in three environments in the USA, 69 traits in eight environments in Germany, 149 traits in 10 environments in Russia, and 28 traits in four environments in India (292 traits in 25 environments) with 7584 SNPs (292 × 7584 = 2 214 528 data points). A total of 874 QTLs were detected with limit of detection (LOD) scores of 2.01–3.0 and 432 QTLs were detected with LOD > 3.0. Moreover, 769 QTLs could be assigned to 183 clusters based on the common markers and relative proximity of related QTLs, indicating gene-rich regions throughout the A, B, and D genomes of common wheat. This upgraded genotype–phenotype information of ITMI/MP can assist breeders and geneticists who can make crosses with suitable RILs to improve or investigate traits of interest.     

Melatonin protects against experimental immune ovarian failure in mice

Experimental immune ovarian failure induced in CBA mice by either administration of xenogenic anti-ovarian antibodies or immunization with allogenic ovarian extracts impaired the meiotic maturation of oocytes and increased apoptosis of follicular cells. Immunization was accompanied with the inflammation and active immune reaction, as shown by the enlargement of regional lymph nodes, the increase of apoptosis in cultured lymph node cells and the increase of band and segmented neutrophil percentage in the blood. Triple injections of melatonin (5 mg/kg of the body weight) an hour before antibodies administration restored the meiotic maturation of oocytes and supported the survival of follicular and lymph node cells. In contrast, melatonin application upon immunization was not effective to prevent the ovary impairment and cell death. It is concluded that melatonin protects against immune ovary failure induced by xenogenic anti-ovarian antibodies.     

Tritium planigraphy comparative structural study of tobacco mosaic virus and its mutant with altered host specificity.

Spatial organization of wild-type (strain U1) tobacco mosaic virus (TMV) and of the temperature-sensitive TMV ts21-66 mutant was compared by tritium planigraphy. The ts21-66 mutant contains two substitutions in the coat protein (Ile21-->Thr and Asp66-->Gly) and, in contrast with U1, induces a hypersensitive response (formation of necroses) on the leaves of plants bearing a host resistance gene N' (for example Nicotiana sylvestris); TMV U1 induces systemic infection (mosaic) on the leaves of such plants. Tritium distribution along the coat protein (CP) polypeptide chain was determined after labelling of both isolated CP preparations and intact virions. In the case of the isolated low-order (3-4S) CP aggregates no reliable differences in tritium distribution between U1 and ts21-66 were found. But in labelling of the intact virions a significant difference between the wild-type and mutant CPs was observed: the N-terminal region of ts21-66 CP incorporated half the amount of tritium than the corresponding region of U1 CP. This means that in U1 virions the CP N-terminal segment is more exposed on the virion surface than in ts21-66 virions. The possibility of direct participation of the N-terminal tail of U1 CP subunits in the process of the N' hypersensitive response suppression is discussed.     

Thermodynamic,kinetic, and structural basis for recognition and repair of 8-oxoguanine in DNA by Fpg protein from Escherichia coli

X-ray analysis does not provide quantitative estimates of the relative importance of the molecular contacts it reveals or of the relative contributions of specific and nonspecific interactions to the total affinity of specific DNA to enzymes. Stepwise increase of DNA ligand complexity has been used to estimate the relative contributions of virtually every nucleotide unit of 8-oxoguanine-containing DNA to its total affinity for Escherichia coli 8-oxoguanine DNA glycosylase (Fpg protein). Fpg protein can interact with up to 13 nucleotide units or base pairs of single- and double-stranded ribo- and deoxyribo-oligonucleotides of different lengths and sequences through weak additive contacts with their internucleotide phosphate groups. Bindings of both single-stranded and double-stranded oligonucleotides follow similar algorithms, with additive contributions to the free energy of binding of the structural components (phosphate, sugar, and base). Thermodynamic models are provided for both specific and nonspecific DNA sequences with Fpg protein. Fpg protein interacts nonspecifically with virtually all of the base-pair units within its DNA-binding cleft: this provides approximately 7 orders of magnitude of affinity (Delta G degrees approximately equal to -9.8 kcal/mol) for DNA. In contrast, the relative contribution of the 8-oxoguanine unit of the substrate (Delta G degrees approximately equal to -0.90 kcal/mol) together with other specific interactions is <2 orders of magnitude (Delta G degrees approximately equal to -2.8 kcal/mol). Michaelis complex formation of Fpg protein with DNA containing 8-oxoguanine cannot of itself provide the major part of the enzyme specificity, which lies in the k(cat) term; the rate is increased by 6-8 orders of magnitude on going from nonspecific to specific oligodeoxynucleotides.     

A Model of the Membrane-bound Cytochrome b5-Cytochrome P450 Complex from NMR and Mutagenesis Data

Microsomal cytochrome b₅ (cytb₅) is a membrane-bound protein that modulates the catalytic activity of its redox partner, cytochrome P4502B4 (cytP450). Here, we report the first structure of full-length rabbit ferric microsomal cytb₅ (16 kDa), incorporated in two different membrane mimetics (detergent micelles and lipid bicelles). Differential line broadening of the cytb₅ NMR resonances and site-directed mutagenesis data were used to characterize the cytb₅ interaction epitope recognized by ferric microsomal cytP450 (56 kDa). Subsequently, a data-driven docking algorithm, HADDOCK (high ambiguity driven biomolecular docking), was used to generate the structure of the complex between cytP4502B4 and cytb₅ using experimentally derived restraints from NMR, mutagenesis, and the double mutant cycle data obtained on the full-length proteins. Our docking and experimental results point to the formation of a dynamic electron transfer complex between the acidic convex surface of cytb₅ and the concave basic proximal surface of cytP4502B4. The majority of the binding energy for the complex is provided by interactions between residues on the C-helix and β-bulge of cytP450 and residues at the end of helix α4 of cytb₅. The structure of the complex allows us to propose an interprotein electron transfer pathway involving the highly conserved Arg-125 on cytP450 serving as a salt bridge between the heme propionates of cytP450 and cytb₅. We have also shown that the addition of a substrate to cytP450 likely strengthens the cytb₅-cytP450 interaction. This study paves the way to obtaining valuable structural, functional, and dynamic information on membrane-bound complexes.     

Cytotoxicity of novel derivatives of the spin trap EMPO

Free radicals are involved in different regulatory and pathological processes. The formation of superoxide in living cells or whole organisms is of major interest. ESR spin trapping allows identification of the radicals if proper spin traps are available. Our study investigates the toxicity of novel derivatives of the spin trap EMPO to cultured human lung carcinoma cells (A549), breast carcinoma cells (SKBR3), colon carcinoma cells (SW480) as well as to human fibroblasts (F2000). A dose-dependent decrease of the cell number was observed for all spin traps. At 100mM BuMPO, t-BuMPO and s-BuMPO caused pronounced cell loss (>90%) and increased LDH-release, while DEPMPO, EMPO, PrMPO and i-PrMPO caused only moderate cell loss (<60%) without any effect on the LDH-release after 24h. At 10mM and 50mM the latter agents even decreased LDH-release. 10mM and 50mM of i-PrMPO as well as 10mM PrMPO increased intracellular GSH content acting like antioxidants, whereas 50mM s-BuMPO and PrMPO decreased GSH content by 67% and 38%, respectively. Staining for apoptotic nuclei did not reveal any differences between controls and treated cultures indicating necrotic cell death possibly due to membrane toxicity. The following toxicity ranking was obtained: t-BuMPO>BuMPO>s-BuMPO>PrMPO>i-PrMPO approximately DEPMPO approximately EMPO. The least toxic compounds were DEPMPO (LD(50)=143 mM for SW480, 117 mM for A549 or 277 mM for F2000) and i-PrMPO (LD(50)=114 mM for SKBR3), the most toxic one was t-BuMPO (LD(50)=5-6mM for all cell types). In conclusion, up to 50mM i-PrMPO (t(1/2)=18.8 min) and up to 10 mM s-BuMPO (t(1/2)=26.3 min) can be recommended for further investigation of superoxide in biological systems.     

Photoluminescence of Fullerene C60 Thin Film in Plasmon-Coupled Monolayer of Au Nanoparticles – C 60 Film – Al Film Nanostructure

Plasmonics - The plasmon-enhanced photoluminescence of fullerene C60 thin film has been studied to reveal the dependence of the magnitude of plasmonic field in coupled nanosystem monolayer of gold...